It was implemented with Patch 1.2.1 alongside the Perks of The Shape and Laurie Strode, the first ones to use this new mechanic before it became part of every Trial.
The Obsession Mechanic was a major part of the Perks brought into Dead by Daylight in CHAPTER II: The HALLOWEEN® Chapter, bringing with it a then unique interplay of the Killer with their designated Obsession, akin to how in the Halloween franchise, Michael is obsessed with Laurie.
Obsession Mechanic
The Obsession mechanic designates a random Survivor as the Killer's Obsession. The Obsession is marked by the Entity's spider-like legs surrounding the Obsession's icon in the Status HUD and announced by a global sound cue playing at the start of the Trial. The spider-like legs will wiggle from side-to-side whenever the Obsession is in a Chase, giving valuable information to the other Survivors.
Initial Obsession
At the beginning of every Trial in Dead by Daylight, The Entity choses a random Survivor to be the Killer's initial Obsession.
Each Survivor has an equal chance to be picked as The Obsession (25 % in a regular Trial with four Survivors). This chance can be modified using Unlockables (see section below).
Assuming there are no Perks used that can alter the Killer's Obsession, the initial Obsession will usually remain the Obsession for the entirety of the Trial.
Chance Modifiers
Some Perks and Add-ons have the ability to influence The Entity's decision on which Survivor will become the Killer's initial Obsession. They always do so by either adding (increasing the Odds) or subtracting (reducing the Odds) by a modifier of 100 %.
Contrary to popular belief, and due to how probability works in Dead by Daylight, this modifier does not guarantee that one is chosen as the initial Obsession (+100 %), nor does it guarantee the opposite, that one is not' chosen (-100 %).
In either case, there is a minuscule chance that one becomes or does not become the initial Obsession regardless.
Changing Obsession
Some Perks have the ability to change a Killer's Obsession under specific circumstances. Any buffs or debuffs associated with the Obsession will transfer from the initial to the new Obsession and any potential subsequent Obsession.
Some Perks also have the ability to assign a new Obsession if the previous one has died.
Sound Cues
Cue
Condition
This Cue plays whenever the Obsession is chosen at the beginning of or during a Trial.
This Cue plays whenever the current Obsession is killed or sacrificed by the Killer.
Unlockables
If any Survivor or the Killer brings any of the following Unlockables, the Obsession Mechanic is triggered for the Trial:
It is as if a latent part of yourself has awakened.
You feel like you can reach out beyond yourself for assistance.
<p>When you or the '''''Obsession''''' are injured, you both see each other's Auras.
* After healing the '''''Obsession''''' or being healed by the '''''Obsession''''', you both gain the '''''Haste''''' '''Status Effect''', moving at an increased speed of '''<span class="luaClr clr clr2" style="color: #e8c252;">5</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">6</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">7</span> %''' until you are no longer within '''<span class="luaClr clr clr2" style="color: #e8c252;">16 metres</span>''' of each other.
* If you are the '''''Obsession''''', ''Blood Pact'' deactivates.
<p>Lowers the odds of becoming the Killer's initial '''''Obsession''''' by '''<span class="luaClr clr clr2" style="color: #e8c252;">-100 %</span>'''.
<p>''The Killer can only be '''obsessed''' with one Survivor at a time.''
It is as if a latent part of yourself has awakened.
You feel like you can reach out beyond yourself for assistance.
When you or the Obsession are injured, you both see each other's Auras.
After healing the Obsession or being healed by the Obsession, you both gain the HasteStatus Effect, moving at an increased speed of 5/6/7 % until you are no longer within 16 metres of each other.
If you are the Obsession, Blood Pact deactivates.
Lowers the odds of becoming the Killer's initial Obsession by -100 %.
The Killer can only be obsessed with one Survivor at a time.
Using whatever is at hand, you stab your aggressor in an ultimate attempt to escape.
<p>After being unhooked or unhooking yourself, ''Decisive Strike'' activates for the next '''<span class="luaClr clr clr2" style="color: #e8c252;">40</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">50</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">60</span> seconds''':
*When being grabbed or picked up by the Killer, succeed a Skill Check to automatically escape their grasp, stunning them for '''<span class="luaClr clr clr2" style="color: #e8c252;">5 seconds</span>'''.
*Successfuly stunning the Killer will disable ''Decisive Strike'' for the remainer of the Trial and result you in becoming the '''''Obsession'''''.
<p>While ''Decisive Strike'' is active, the following interactions will deactivate it:
*Repairing a Generator.
*Healing yourself or other Survivors.
*Cleansing or Blessing a Totem.
*Sabotaging a Hook.
*Unhooking other Survivors.
<p>Increases the odds of becoming the Killer's initial '''''Obsession''''' by '''<span class="luaClr clr clr2" style="color: #e8c252;">+100 %</span>'''.
''The Killer can only be '''obsessed''' with one Survivor at a time.''
Using whatever is at hand, you stab your aggressor in an ultimate attempt to escape.
After being unhooked or unhooking yourself, Decisive Strike activates for the next 40/50/60 seconds:
When being grabbed or picked up by the Killer, succeed a Skill Check to automatically escape their grasp, stunning them for 5 seconds.
Successfuly stunning the Killer will disable Decisive Strike for the remainer of the Trial and result you in becoming the Obsession.
While Decisive Strike is active, the following interactions will deactivate it:
''For the People'' is only active while at full health.
* Press the ''Active Ability button'' while healing another Survivor without a [[Med-Kit]] to instantly heal them '''<span class="luaClr clr clr2" style="color: #e8c252;">1</span>''' Health State.
* You become the '''''Obsession'''''.
<p>''For the People'' causes the '''''Broken''''' '''Status Effect''' for '''<span class="luaClr clr clr2" style="color: #e8c252;">80</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">70</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">60</span> seconds''' after using it.
Lowers the odds of becoming the Killer's initial '''''Obsession''''' by '''<span class="luaClr clr clr2" style="color: #e8c252;">-100 %</span>'''.
''The Killer can only be '''obsessed''' with one Survivor at a time.''
You risk life and injury for others.
For the People is only active while at full health.
Press the Active Ability button while healing another Survivor without a Med-Kit to instantly heal them 1Health State.
You become the Obsession.
For the People causes the BrokenStatus Effect for 80/70/60 seconds after using it.
Lowers the odds of becoming the Killer's initial Obsession by -100 %. The Killer can only be obsessed with one Survivor at a time. "We can write our own story and decide how it really ends." — Zarina Kassir
Evil has a way of always finding you.
<p>After triggering your '''<span class="luaClr clr clr2" style="color: #e8c252;">third</span>''' ''Protection Hit'', ''Mettle of Man'' activates and you are protected by the '''''Endurance''''' '''Status Effect''':
* Any damage taken that would put you into the Dying State from the Injured State is blocked.
* When you are healed again, your Aura will be revealed to the Killer whenever you are farther than '''<span class="luaClr clr clr2" style="color: #e8c252;">12</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">14</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">16</span> metres''' away.
<p>''Mettle of Man'' deactivates the next time you are put into the Dying State.
Increases the odds of becoming the Killer's initial '''''Obsession''''' by '''<span class="luaClr clr clr2" style="color: #e8c252;">+100 %</span>'''.
<p>''The Killer can only be '''obsessed''' with one Survivor at a time.''
Evil has a way of always finding you.
After triggering your thirdProtection Hit, Mettle of Man activates and you are protected by the EnduranceStatus Effect:
A supernatural bond links you to the Killer.
<p>Whenever the Killer reads your Aura and for the same duration as they do so, ''Object of Obsession'' activates:
* The Killer's Aura is revealed to you.
* '''Increases''' your Action speeds in Repairing, Healing, and Cleansing by '''<span class="luaClr clr clr2" style="color: #e8c252;">2</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">4</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">6</span> %'''.
<p>If you are the '''''Obsession''''', your Aura is automatically revealed to the Killer for '''<span class="luaClr clr clr2" style="color: #e8c252;">3 seconds</span>''' every '''<span class="luaClr clr clr6" style="color: #ff8800;">30 seconds</span>'''.
<p>Increases the odds of becoming the Killer's initial '''''Obsession''''' by '''<span class="luaClr clr clr2" style="color: #e8c252;">+100 %</span>'''.
''The Killer can only be '''obsessed''' with one Survivor at a time.''
A supernatural bond links you to the Killer.
Whenever the Killer reads your Aura and for the same duration as they do so, Object of Obsession activates:
The Killer's Aura is revealed to you.
Increases your Action speeds in Repairing, Healing, and Cleansing by 2/4/6 %.
If you are the Obsession, your Aura is automatically revealed to the Killer for 3 seconds every 30 seconds.
Increases the odds of becoming the Killer's initial Obsession by +100 %. The Killer can only be obsessed with one Survivor at a time.
As more of your friends fall to the Killer, you become shrouded in isolation and the Killer's Aura-reading abilities towards you are disrupted.
<p>Each time a Survivor other than yourself is killed or sacrificed, ''Sole Survivor'' gains '''<span class="luaClr clr clr2" style="color: #e8c252;">1 Token</span>''', up to a maximum of '''<span class="luaClr clr clr6" style="color: #ff8800;">3 Tokens</span>''':
* Each Token grants a stack-able radius of '''<span class="luaClr clr clr2" style="color: #e8c252;">20</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">22</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">24</span> metres''' within which the Killer is unable to read your Aura, up to a maximum of '''<span class="luaClr clr clr2" style="color: #e8c252;">60</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">66</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">72</span> metres'''.
<p>Increases the odds of becoming the Killer's initial '''''Obsession''''' by '''<span class="luaClr clr clr2" style="color: #e8c252;">+100 %</span>'''.
''The Killer can only be '''obsessed''' with one Survivor at a time.''
As more of your friends fall to the Killer, you become shrouded in isolation and the Killer's Aura-reading abilities towards you are disrupted.
Each time a Survivor other than yourself is killed or sacrificed, Sole Survivor gains 1 Token, up to a maximum of 3 Tokens:
Each Token grants a stack-able radius of 20/22/24 metres within which the Killer is unable to read your Aura, up to a maximum of 60/66/72 metres.
Increases the odds of becoming the Killer's initial Obsession by +100 %. The Killer can only be obsessed with one Survivor at a time.
The display of your Powers creates a whirlwind of panic that spreads throughout the land.
You become '''''obsessed''''' with one Survivor.
Hitting the '''''Obsession''''' with a ''Basic Attack'' causes them to emit a Terror Radius of '''<span class="luaClr clr clr2" style="color: #e8c252;">32 metres</span>''' for the next '''<span class="luaClr clr clr2" style="color: #e8c252;">20</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">25</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">30</span> seconds'''.
* You are granted the '''''Undetectable''''' '''Status Effect'''.
* The '''''Obsession''''' hears their own Terror Radius.
<p>''You can only be '''obsessed''' with one Survivor at a time.''
The display of your Powers creates a whirlwind of panic that spreads throughout the land.
You become obsessed with one Survivor.
Hitting the Obsession with a Basic Attack causes them to emit a Terror Radius of 32 metres for the next 20/25/30 seconds.
You can only be obsessed with one Survivor at a time. "And terror shall take hold of a defiant non-believer, who shall falsely announce my arrival." — (The Tablet of Adiris, 48.9)
Each time you hook a Survivor other than your '''''Obsession''''', you gain '''<span class="luaClr clr clr2" style="color: #e8c252;">1 Token</span>''':
* For as long as the '''''Obsession''''' is alive, all other Survivors suffer from a stack-able '''<span class="luaClr clr clr2" style="color: #e8c252;">2</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">2.5</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">3</span> %''' penalty to Repairing, Healing, and Sabotaging speeds per Token, up to a maximum of '''<span class="luaClr clr clr2" style="color: #e8c252;">22</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">27.5</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">33</span> %''' or '''<span class="luaClr clr clr6" style="color: #ff8800;">11 Tokens</span>'''.
* The '''''Obsession''''' is unaffected by this penalty and instead granted a permanent '''<span class="luaClr clr clr8" style="color: #d41c1c;">33 %</span>''' Action Speed bonus to Unhooking and Healing other Survivors.
<p>''You can only be '''obsessed''' with one Survivor at a time.''
You become obsessed with one Survivor.
Each time you hook a Survivor other than your Obsession, you gain 1 Token:
For as long as the Obsession is alive, all other Survivors suffer from a stack-able 2/2.5/3 % penalty to Repairing, Healing, and Sabotaging speeds per Token, up to a maximum of 22/27.5/33 % or 11 Tokens.
The Obsession is unaffected by this penalty and instead granted a permanent 33 % Action Speed bonus to Unhooking and Healing other Survivors.
You can only be obsessed with one Survivor at a time.
You lurk in the shadows, eliminating your victims one by one.
Each time you hook your '''''Obsession''''', you gain '''<span class="luaClr clr clr2" style="color: #e8c252;">1 Token</span>''', up to a maximum of '''<span class="luaClr clr clr2" style="color: #e8c252;">2</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">3</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">4</span> Tokens''':
* While in a Chase, your Terror Radius is reduced by '''<span class="luaClr clr clr6" style="color: #ff8800;">4 metres</span>''' per accumulated Token.
* When a Survivor rescues the '''''Obsession''''' from the Hook, that Survivor will become the new '''''Obsession'''''.
<p>''You can only be '''obsessed''' with one Survivor at a time.''
You become obsessed with one Survivor.
You lurk in the shadows, eliminating your victims one by one.
Each time you hook your Obsession, you gain 1 Token, up to a maximum of 2/3/4 Tokens:
While in a Chase, your Terror Radius is reduced by 4 metres per accumulated Token.
When a Survivor rescues the Obsession from the Hook, that Survivor will become the new Obsession.
You can only be obsessed with one Survivor at a time. "You have no idea what I have planned for you. It'll be in the news for weeks. I'll make sure of that." — The Ghost Face
Your act of servitude to The Entity has not gone unnoticed.
Each time a Survivor is hooked for the first time, ''Grim Embrace'' gains a Token. Upon reaching '''<span class="luaClr clr clr2" style="color: #e8c252;">4 Tokens</span>''' ''Grim Embrace'' activates:
*The Entity blocks all Generators for '''<span class="luaClr clr clr2" style="color: #e8c252;">30</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">35</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">40</span> seconds'''.
*The Aura of the '''''Obsession''''' is revealed to you for '''<span class="luaClr clr clr6" style="color: #ff8800;">5 seconds</span>'''.
Your act of servitude to The Entity has not gone unnoticed.
Each time a Survivor is hooked for the first time, Grim Embrace gains a Token. Upon reaching 4 TokensGrim Embrace activates:
The Entity blocks all Generators for 30/35/40 seconds.
The Aura of the Obsession is revealed to you for 5 seconds.
"Are we nothing but prisoners to our sorrow?" — Carmina Mora
You seek retribution on those who have wronged you.
<p>
*Any Survivor who blinds or stuns you becomes the '''''Obsession'''''.
*Anytime your '''''Obsession''''' switches to another Survivor by any means, that Survivor then suffers from the '''''Oblivious''''' '''Status Effect''' for '''<span class="luaClr clr clr2" style="color: #e8c252;">40</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">50</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">60</span> seconds''' and their Aura is revealed to you for '''<span class="luaClr clr clr2" style="color: #e8c252;">4 seconds</span>'''.
<p>''You can only be '''obsessed''' with one Survivor at a time.''
You seek retribution on those who have wronged you.
Any Survivor who blinds or stuns you becomes the Obsession.
Anytime your Obsession switches to another Survivor by any means, that Survivor then suffers from the ObliviousStatus Effect for 40/50/60 seconds and their Aura is revealed to you for 4 seconds.
You can only be obsessed with one Survivor at a time.
"Only a fool would spit in a demon's face and declare victory." — Renjiro's Doctrine 4:9
Each time you chase your '''''Obsession''''' and let them escape, ''Play with Your Food'' recieves '''<span class="luaClr clr clr2" style="color: #e8c252;">1 Token</span>''', up to a maximum of '''<span class="luaClr clr clr6" style="color: #ff8800;">3 Tokens</span>''':
* Each Token applies a stack-able '''<span class="luaClr clr clr2" style="color: #e8c252;">3</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">4</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">5</span> %''' '''''Haste''''' '''Status Effect''', up to a maximum of '''<span class="luaClr clr clr2" style="color: #e8c252;">9</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">12</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">15</span> %'''.
* Performing ''Basic Attacks'', or ''Special Attacks'' that can damage Survivors, consumes '''<span class="luaClr clr clr8" style="color: #d41c1c;">1 Token</span>'''.
<p>''Play with Your Food'' has a cool-down of '''<span class="luaClr clr clr4" style="color: #ac3ee3;">10 seconds</span>''' on Token-accumulation.
''You can only be '''obsessed''' with one Survivor at a time.''
You become obsessed with one Survivor.
Each time you chase your Obsession and let them escape, Play with Your Food recieves 1 Token, up to a maximum of 3 Tokens:
Each Token applies a stack-able 3/4/5 %HasteStatus Effect, up to a maximum of 9/12/15 %.
Each time a Generator is completed:
* Your Aura is revealed to the '''''Obsession''''' for '''<span class="luaClr clr clr2" style="color: #e8c252;">5</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">4</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">3</span> seconds'''.
* All Survivors' locations are revealed to you for '''<span class="luaClr clr clr2" style="color: #e8c252;">3 seconds</span>'''.
<p>Once all Generators are completed:
* The '''''Obsession''''' suffers from a permanent '''''Exposed''''' '''Status Effect'''.
* You are granted the ability to kill the '''''Obsession''''' by your own hand.
<p>''You can only be '''obsessed''' with one Survivor at a time.''
Each time the '''''Obsession''''' loses a Health State, ''Remember Me'' gains '''<span class="luaClr clr clr2" style="color: #e8c252;">1 Token</span>''':
* '''Increases '''the Opening time of both Exit Gates by '''<span class="luaClr clr clr6" style="color: #ff8800;">4 seconds</span>''' per Token, up to a maximum of '''<span class="luaClr clr clr2" style="color: #e8c252;">8</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">12</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">16</span> additional seconds'''.
* The '''''Obsession''''' remains unaffected by this penalty.
<p>''You can only be '''obsessed''' with one Survivor at a time.''
You become obsessed with one Survivor.
Each time the Obsession loses a Health State, Remember Me gains 1 Token:
Increases the Opening time of both Exit Gates by 4 seconds per Token, up to a maximum of 8/12/16 additional seconds.
The Obsession remains unaffected by this penalty.
You can only be obsessed with one Survivor at a time. "You don't remember? You must. You're my number one, and you'll never wake up again." — Freddy Krueger
Each time you hit a Survivor other than your '''''Obsession''''' with a ''Basic Attack'', ''Save the Best for Last'' gains '''<span class="luaClr clr clr2" style="color: #e8c252;">1 Token</span>''', up to a maximum of '''<span class="luaClr clr clr6" style="color: #ff8800;">8 Tokens</span>''':
* Gain a stack-able '''<span class="luaClr clr clr8" style="color: #d41c1c;">5 %</span>''' Cool-down reduction on successful attacks per Token, up to a maximum of '''<span class="luaClr clr clr4" style="color: #ac3ee3;">40 %</span>'''.
<p>Each time you hit your '''''Obsession''''' with a ''Basic Attack'', ''Save the Best for Last'' loses '''<span class="luaClr clr clr2" style="color: #e8c252;">4</span>'''/'''<span class="luaClr clr clr3" style="color: #199b1e;">3</span>'''/'''<span class="luaClr clr clr4" style="color: #ac3ee3;">2</span> Tokens'''.
* ''When the '''''Obsession''''' is sacrificed or killed, you can neither gain nor lose any more Tokens.''
<p>''You can only be '''obsessed''' with one Survivor at a time.''
You become obsessed with one Survivor.
Each time you hit a Survivor other than your Obsession with a Basic Attack, Save the Best for Last gains 1 Token, up to a maximum of 8 Tokens:
Gain a stack-able 5 % Cool-down reduction on successful attacks per Token, up to a maximum of 40 %.
Each time you hit your Obsession with a Basic Attack, Save the Best for Last loses 4/3/2 Tokens.
When the Obsession is sacrificed or killed, you can neither gain nor lose any more Tokens.
You can only be obsessed with one Survivor at a time.
"Death has come to your little town, Sheriff." — Dr Sam Loomis
Quality of Life: each Trial will now feature an Obsession, regardless of the presence or absence of Obsession Perks.
Trivia
Even though some Perks trigger the Obsession Mechanic, they do not necessarily benefit from it.
Before Patch 3.2.0, which introduced the Unique Wedding Ring Add-on for Keys, there was no way to lower one's chance of being the initial Obsession.
Before Patch 4.7.0, the Perk Nemesis was the only Unlockable using the Obsession mechanic that would not cause Dead by Daylight to chose a Survivor as the Killer's initial Obsession.