Assuming that Sukuna can resist Death spells with CE, Ainz could still hit Sukuna with HP level attacks like fallen down. He has anti-regen attacks. Reality Slash is just a better version of world slash that Ainz doesn't need chants to use.
Actually, another thing I just remembered. Negative energy boosts undead in Overlord, so CE may actually just make Ainz stronger. Positive energy would wound Ainz though but Sukuna hasn't been shown to emit positive energy like Yuta can.
EDIT: Nvm I just remembered Sukuna healed Megumi in Shibuya. Ainz still probably wins, but he's in for a surprise if Sukuna starts punching him with positive energy.
Actually, another thing I just remembered. Negative energy boosts undead in Overlord, so CE may actually just make Ainz stronger. Positive energy would wound Ainz though but Sukuna hasn't been shown to emit positive energy like Yuta can.
EDIT: Nvm I just remembered Sukuna healed Megumi in Shibuya. Ainz still probably wins, but he's in for a surprise if Sukuna starts punching him with positive energy.
TBF if ainz is wearing his holy resistant robes I suspect he'd be able to ignore the positive energy, though that really comes down to the creator of the thread as ainz has a set of data crystals he swaps between outfits, either he's wearing his negate holy damage robes, or his negate fire damage robes.
Negative energy in overlord is able to boost/heal undead. If we assume cursed energy = negative energy a large swath of abilities/powers would simply make ainz stronger/heal his wounds.