A spell?

[ when liem points that out, kaeya falls silent as he considers the possibility of it. if he wasn't fighting back to urge to wander off, he'd likely be trying to find things that can prove it's plausibility, but he is limited in what insights he can offer. the most he can do is think back to what happened to him specifically. ]

I helped someone through her delusions before everything started becoming strange. She thought I was her brother, and I...

[ ... ]

I did have direct contact with her, at one point.