Titan Mode is a reference to Attack on Titan. Press T to activate this mode. It cannot be deactivated until the game is reset or the day ends. Once activated, all students and teachers will grow very large, and their skin and clothing will be removed. The player will revert to the default uniform, but with a brown collar instead of a blue one, a reference to the uniforms worn by the characters in Attack on Titan. The song, "This Is My Choice" by The Kira Justice, will play the entire time.
The player is able to kill the titans, but the hitbox is very specific. They must look above them and aim carefully to kill them.
- If a possessed player's hands dismember a student while in this mode, the hair will be extremely large, but the head will remain small. If any Occult Club member is dismembered this way, their large chokers will float in the sky.
- If a student tries to change in the booth of the Martial Arts Club, they will change into clothes and will no longer remain skinless.
- Titan students run into walls, get stuck, and usually move backwards.
- When a titan is killed, the ragdoll base collapses in on itself, and the body turns into a ball of flesh and rolls all over the place. YandereDev will not fix this bug.
- As of the June 29th, 2016 Build, when a titan student changes their shoes, their texture will break.
- The original music for this mode was Attack on Titan's first theme song, "Feuerroter Pfeil und Bogen", also known as "Guren no Yumiya". It was replaced with an original song in the February 21st, 2016 Build. It was changed again in the March 15th, 2016 Build to "This Is My Choice" by The Kira Justice
- This mode was implemented in the February 1st, 2015 Build.
- The game's warning referred to this mode, saying that this game contains "titans". This warning was later removed because YandereDev said that it was "cringey".
- To not get in trouble for having naked minors, YandereDev removed the Titan's skin as of the February 1st, 2016 Build. They had a red feathery texture, but were given more realistic muscle in the February 21st, 2016 Build. Druelbozo is credited with making the new skin.
- This mode's name may be changed to Colossus Mode at some point.
- Genka Kunahito, Rival-chan, the delinquents, Senpai, Muja Kina and the placeholder club leaders are not affected by this mode.
- As of the June 29th, 2016 Build, when a titan student changes their shoes, the shoes will match the student's size.