Question: how did kozuki oden die?
Answer: We know that Orochi publicly “executed” Oden by boiling him alive. But there are hints that he could have survived: 1-When prisoners arrive in Impel Down, they are put in boiling water known as Hells Hot Tub to disinfect and sterilize them. Ace, Jinbe and Crocodile didn't even flinch when they went through this.