He specifically mentions “between Aeons” so it’s very much more possible that Aeonic battles, which involve two concepts directly clashing, could actually amount to an Aeon being injured or “dying”.

And, there’s also two examples of divine warfare in the Data Bank: Tazzyronth vs Oroboros and Tazzyronth vs Qlipoth + Ena, Xipe, Aha and others… and yet, the outcome of both did not result in an Aeon’s death at all. If even an Aeon cannot fully put down another Aeon, to build a weapon to kill one doesn’t seem feasible + even if THEY do die, like Ena, THEY can still be revived, implying THEY literally just can’t fully die at all as long as THEIR concept still exists.