That's not her tooth that's her lip and it's like that because her face is deformed as a result of down syndrome. Her hyperactivity is a side effect of ADHD and the reason she's so nice and sweet is because she's a literal retard. Her combat strength comes from her tard powers. Anyone who thinks otherwise is deluding themselves.
Also Mordred is the worst character in the series, too big for her own britches. The way she acts entitled despite being a rape baby is beyond me.
There is honestly no better grill than pic related, they are just so fucking cool, nothing will ever come in comparison to them. Character design is on point and they even know how to fight well and not act like a retard. Can your waifu do that, anon? I thought not. Get out of here, kid.