While I do find this whole thing (but especially Yoshika) adorable, I can't help but feel a bit sad about their relationship in general. Even when it's super light-hearted and cute like its portrayed here, I always wonder about how much of it is Yoshika's true affection for Seiga and how much is just part of her being controlled by Seiga, and how long it could last. Even here, there's the implication that Yoshika's brain is rotting further with Seiga mentioning how it took her longer to remember.
I still like the pairing nonetheless. Dark Fluff is nice too. Also I'm probably reading into this WAY too much.