The Teacher is either an unused or joke Killer in Dead by Daylight .
Around July 2016, three in-game files were added to the Game's icon folder:
The addition of those files fuelled speculations that they belonged to a new, upcoming Killer, likely Teacher-themed. This was further fuelled by an announcement by the Developers, that were working on the first ever Chapter DLC, supposed to be released about in August 2016.
Eventually, the new Killer turned out to be The Nurse and The Teacher's files remained unused ever since.
Judging from Detention , The Teacher would likely have been armed with a Ruler that would have had a blade attached to it.
The potential effects of Detention remain unknown.
There is only one known Perk that would have belonged to The Teacher:
|BASE GAME||CHAPTERS I-III (1-3)
+ PARAGRAPH I (1)
|CHAPTERS IV-VII (4-7)||CHAPTERS VIII-XI (8-11)||PARAGRAPH III (3)|
+ CHAPTERS XIII+XIV (13+14)
|Dwight Fairfield||Nea Karlsson||Feng Min||Kate Denson||Ash Williams|
|Meg Thomas||Laurie Strode||David King||Adam Francis||Nancy Wheeler|
|Claudette Morel||Ace Visconti||Quentin Smith||Jeff Johansen||Steve Harrington|
|Jake Park||Bill Overbeck||David Tapp||Jane Romero||Yui Kimura|
|CHAPTERS XV-XVIII (15-18)||CHAPTER XIX (19)|
|Zarina Kassir||Yun-Jin Lee|
|BASE GAME||CHAPTERS I-III (1-3)||CHAPTERS IV+V (4+5)
+ PARAGRAPH II (2)
|CHAPTERS VI-VIII (6-8)||CHAPTERS IX-XI (9-11)|
|The Trapper - Evan MacMillan||The Nurse - Sally Smithson||The Doctor - Herman Carter||The Nightmare - Freddy Krueger||The Spirit - Rin Yamaoka|
|The Wraith - Philip Ojomo||The Shape - Michael Myers||The Huntress - Anna||The Pig - Amanda Young||The Legion - Frank, Julie, Susie, Joey|
|The Hillbilly - Max Thompson Jr.||The Hag - Lisa Sherwood||The Cannibal - Bubba Sawyer||The Clown - Jeffrey Hawk||The Plague - Adiris|
|CHAPTERS XII-XIV (12-14)||CHAPTERS XV-XVII (15-17)||CHAPTERS XVIII+XIX (18+19)|
|The Ghost Face - Danny Johnson||The Deathslinger - Caleb Quinn||The Twins - Victor & Charlotte Deshayes|
|The Demogorgon - Demogorgon||The Executioner - Pyramid Head||The Trickster - Ji-Woon Hak|
|The Oni - Kazan Yamaoka||The Blight - Talbot Grimes|
|Benedict Baker||The Entity||The Observer||Vigo||and many more...|
|The Smasher||The Teacher|