I had a lot of back and forth about the translation of this. It never got anywhere since no one could make heads or tails of it, so the transliteration was settled for.
Is this really it? The kanji/furi is what threw people off.
Edit: Read and noted. It's too late in the game to do anything about it anyway.
Gaburi
Gabriel
I've left both the names, since がぶり is Gaburi (Gabriel), but I'm not sure if the other kanji has a particular meaning here. Also, Gaku-Touhou (the group which translated this whole doujin) translated this as "Gaburi".
I guess Hijiri's calling that youkai Gaburi since the name Gabriel means also "God's force" or "God's hero", and well, you've just seen what happened. Anyway, I'm still talking too much and this is only a guessing, so, sorry ""