You stalk around the bundle of neurons, the core of the Witch, examining it with both your eyes and your magical senses. To your eyes, it's just a quivering lace of yellowish-green nerves, twitching spasmodically despite the fact that it has no muscle. To your other senses...
It's Hildegard. It is fundamentally the Witch, the tiniest mass of coherent Grief, slowly, constantly everting more Grief, stripped bare of the trappings of its form. Insofar as you can tell, this is the nexus around which a Grief Seed forms, the tiny wellspring of Grief you find in a Soul Gem. You can feel it stuggling to draw in more Grief from the Barrier, presumably to reform and fight back.
You nudge it with your Grief manipulation, trying to elicit a reaction from it. Sudden, it twitc-
Despair lances through your mind, a powerful, sledgehammer blow that rips right through you. Useless. Why did you ever imagine you could help? Now Mami and Homura are looking to you, and you're going to fail an-
You scream, and break it off, staggering back a step and dropping to a knee with a wet squelching noise, supporting yourself on your hammer. Harsh breaths whoosh out of you in fast gasps, your mouth dry and heart thundering in a way that it hasn't since the beginning of this fight.
That... was... something.
With trembling fingers, you cleanse your own Soul Gem, siphoning the Grief off in thick, ropy streamers that you add to your wings. You don't have to look to tell that there's far more corruption in there than there's ever been to date.
You shakily rise to your feet, leaning heavily on your warhammer, the head of which sinks into the floor with a fleshy squelch as you put your weight on it. You stare at the Witch.
It... it makes sense, you suppose. A Witch is formed of a puella magi in the deepest, darkest pits of despair, and there'd be little to move it from there.
You... probably don't want to actually try prodding that further, you decide, and you steel yourself to try something else.
Maybe if you tried removing the Grief from it and replace it with magic? If a Witch is powered by Grief and a puella magi of, well, magic... Well, it's worth a shot, you figure, reaching out with shaky fingers-
No. No, you're going to rest a few more minutes first. Echoes of that yawning abyss that you were teetering over still reverberate through you.
For a while, you simply breathe, ignoring the heavy, coppery tang of blood hanging in the air and the horrid, wet squelching noises underfoot as you let your hammer support your weight again.