Board Thread:Manga/@comment-29919227-20160909220906/@comment-24407809-20160916030233

I'll rephrase my theory a bit: maybe Zeke's scar didn't heal because that's what it is: a scar. The Titan serum speeds and enhances a human's healing ability, but does it completely erase previous injuries that have already healed? Yes, Armin's burns were healed, but he had just sustained them, and hadn't recovered yet. Maybe Zeke's scar wasn't healed because there was nothing to heal when he was given the serum, just tissue that (while scarred) had already healed naturally on its own.