Turquoise
Also available as: Android mod, Demo
Most mods install on top of a fresh copy of DDLC, free from ddlc.moe. Follow the author's instructions, and keep a clean copy of the game.
About this mod
After three years of work, at long last, I'm pleased to present Turquoise! :D This is a Sayonika mod, featuring a romantic relationship between Sayori and Monika, told from Sayori's point of view. It features roughly ten hours of new content over 13 in-game days. It can be considered to be an alternate timeline from the original game, so don't assume you know everything about the story and/or characters.