Bang her in prologue/whenever it's a option, never try to sneak attack her, in the dream with her pick a yes instead of the no, build Mallach temple (MAYBE optional in a later patch) a mysterious cat will pop up eventually later in the bottom right corner of the temple (think it's rng), that'd be her, when you talk with Mallach answer it's cause she wants a child, talk with her at her home afterward in the ways between about redemption. MAKE SURE YOU SAY YOU WILL GIVE IT OR NOT SURE not no, never sell your soul to anyone else, in khor minos treat calise well because she either is kasyrra or is deeply connected to her (their backstories are the same and kas relationship affects calises) .
For bonus optional content enable holidays in options, wander in the forest for Halloween kas, go to winter city for party and look for the mysterious person, give aileh 30 something facial scrubs, bang tf outta her until she removes piercings in a scene, bang her again, have freja, then during the raising process there'll be short but meaningful kas scenes. Also lose at some bosses for bad ends with her, of note are the one at the spectral blacksmith in the glacial rift, the centaurs when saving caits dad, losing to whisper in "getting into the closet", losing to jyrranaz in the hive, the tomb raiders in calises ring quest, and losing to vacia and Bruno