#it’s also kinda funny that the original name from ars goetia is focalor not focalors

[glouris]

Gross oversimplification of how Furina & Focalors split works

The hydro archon - Furina + Focalors, one being

Furina, separated - body and spirit of the hydro archon

Focalors, separated - divinity of the hydro archon

Now, imagine that you’re Furina, while Focalors is some aspect of yourself - like your ability to play the piano. This aspect breaks away from you, taking all the memories connected to it - you learning how to play, people you knew in music school, crying over homework, everything. After that, it becomes a formless entity that haunts a piano in your living room, and plays it from the inside, directly on the strings.

Despite this entity being separate, it’s still you, because it’s you that learned the piano, it’s your skills, memories, emotions. This aspect of yourself is incomplete without the rest of you, and you’re incomplete with a chunk of your life missing, but it’s okay because you can still move on without knowing how to play the piano. 

Genshin goes out of its way to state that Furina and Focalors are one in the same several times. Focalors is not a clone, sister, mother - she doesn’t even have a body. Focalors is Furina’s allegorical ability to play the piano, she’s the act of “Furina being a god” itself.