Redbad was king (or duke) of Frisia. He famously declared that he would prefer to spend eternity in hell. This fate is well deserved for a king who inspired fear in both his colleagues and his enemies. Such a powerful figure can only be doomed to hell rather than heaven.
People who say they want to be in Hell are the kind of tryhards who are better of there anyway. Regardless of his actions, that kind of sentiment is worth sending someone to hell for in the first place. Our lord and savior Jesus Christ would not look fondly on treating Hell as a joke.
Hell is not a real place, it as metaphiscal state where all joy and plesantness has been stripped and there is only pain and suffering. No matter what anyone has done, no one truely deserves to spend an infinate amount of time feeling nothing but pain and suffering with no hope for relief.
At the time of Redbad, in the eight century, the catholic church was as evil and corrupt as any other institution and Redbad made that statement shortly before he was scheduled to convert from paganism. He backed out of the conversion when he learned that none of his ancestors would be in heaven, since they were pagans. Given his ignorance and motives, he can be forgiven and is probably in Heaven, if it exists.