Throwing my two cents in for the coco/kson in a pseudo fate holy grail war.
If I remember right the original proposal/prompt for this was to basically have her as a Gilgamesh type incarnated servant who summons Kanata as her servant. Though I do like this spin on it of having both Coco as servant and Kson as master
>>67797185 especially since it could absolutely be a great twist to pull if Kson isn't a main character since "Master K" could be used as either a way to hide that Coco will be one of the other servants or be revealed as Kanata's master.
For servant identities, whoever writes this has the opportunity to actually make it a "fair mystery" about guessing who's who since the reference pool of "viable guess" isn't everyone in the public domain but effectively just restricted to holomems. So you can actually guess who's being foreshadowed.