Garp was (for some reason) presented as way more villainous than he ever was in the manga
Even when we didn't know his identity, he was never presented as some sort of ruthless, ends-justify-the-means type of guy.
Granted, I've yet to watch the last two episodes, so I don't know how his arc is resolved in this Season. But from what I've seen he's far removed from the unhinged but jolly manga and anime Garp