Third panel: Wow, he found the weak point REALLY FAST!
And yep, Kyubey is probably classifiable as an apostle... just look at the "Madoka - Kyubey's true form" pool... some of those are definitely grotesque enough to be such.
Third panel: Wow, he found the weak point REALLY FAST!
My theory: His Brand of Sacrifice (which is barely visible in Panel 2) reacts to Witches the same way it does to evil supernatural entities in the Berserkverse (not limited to Apostles and the God Hand, BTW), and he noticed in Panel 2 that the Brand didn't stop bleeding (the typical reaction to evil spirits' presence).
I have no earthly clue......what's going on right now. Srsly.