Hard to explain but there are enough satire/joke videos about it. It's basically the western version of being a chuuni. I'm mostly talking about the way they dress, or he specifically chose to dress here (plague mask, the naming of his character etc.) basically, imagine Shadowgarden-Anime but while trying to be serious. I can endure a certain amount of it and even like it that way, but it can be dangerously close to being extremely silly.
Anyway:
I'm honestly not sure if he actually needed the help of his father and his troops. Well... he needed his father because the previous corpse would've escaped, but not actually to defeat them, as far as I remember.
I actually believed that he called in reinforcements to be safe or to make it plausible that he is only at a "certain" level.
Although I'm not sure if he even wants to keep hiding his abilities now, since he no longer plans on killing his father.