Here is the full list of all 25 Conor Origins - there are T Trilogy achievements.
Hear Dave's confession
Try to stop worrying about Dave
Get abandoned by Mila
Get the ending where Dave disappears.
Spend your life trying to find Dave's killer
Finished reading through They Cannot Hear Me
Give up on escaping prison
Found the wrong key
Escape your cell
Request to stay with Mila
Agree to split up with Mila
Leave Mila behind
Get the true ending in Trapped
Spend time with Dave but miss chance to confess
Enjoy manga with Dave
Support Dave's interests
Get arrested for attempted murder
Let Jolie have Dave
Have Dave save your life
Swear to be there for Dave when he's in trouble
Accept Dave for who he is and go with him
Confess your feelings to Dave
Got away from Dave
Get together with Dave after escaping death
Burn to death