His brain told him it was a humanoid form, which approached the border of the distortion, but it too seemed to be made out of this anomalous parallel lines. It lacked everything that could define it as human.
I really enjoy the disconnect here. An illuminated downpour of rain. Something humanoid. You're playing with interesting clues here, but very scant. One can tell this is a part of something much broader. I'm quite intrigued (and glad it continues somewhere!).
It is very difficult for me to articulate a description of what I perceive to be boundary, or the layered onion(s) of universes or alternate realities breaking down, in a visual sense - allowing traversal between them - and then to ponder on what the consequences of that might be.
I have seen a lot of cinema / tv doing this - but I do not believe I have read about it described in books all that often until I read Cixin Liu's Death's End / The Dark Forest (part of the Three Body saga - there it is done superbly, but here...
I think I can improve. I can always improve.