"Unlikely," Eddy finally says a few moments after the mushroom finishes.
"The fact that you can still speak freely about it and that there are moments where he appears to be dormant means that it is not too far gone," he ignites a small flame in his paw and quickly extinguishes it as he speaks, "If you want evidence of that, simply consider your own situation. If that fragment can consume and overtake your soul, then yours can do the same to it."
He slowly writes out the Giant Rune for death in the air with the smoke and blows it towards the fungus, then places a paw just above his cap just as the smoke passes in between. He closes his eyes a moment and focuses harder on the souls.
"Beyond my power to separate safely," he speaks after a moment, "But, I genuinely believe that it is within your power to overcome, maybe even keep a bit of the power he grants you as you do."
He strokes his chin thoughtfully, "I am no cleric or arcanist, but perhaps, and this is just a guess, you could try combatting it by trying to starve it of negative energy? Hard to avoid when on missions, but maybe time spent fasting, praying, or acting selflessly could work? Rather hypocritcal of me to suggest I know, but maybe worth a shot. There are likely smarter folks in the guild on these matters, I've only removed a soul from an object, I can see them when close enough, and I can strike them, but this is certainly more involved."