The only thing that doesn't make sense is that he aggroes. Support builds with low damage, low defense/hp and high evasion are feasible, but normally you want to keep them out of the fray anyway and have the tank aggro while they support the tank and/or the DPS build. Like in DAI you wouldn't...
Just my type of manga, a badass MC that's not an idiot or an asshole. Rather than OP, he is smart enough to pick his battles. Reminds me of Grancrest War, 8.5/10, the only thing I dislike is the pacing and the out-of-place "romance"