Doom Mantis is what would result if a Doom Blade were to go to a sort of dojo to hone it's skills and control it's strength; It converts from a sort of brutal, dirty, and self-harming berserker frog to a calm, cool mantis capable of dealing low EN damage with no recoil.
Doom Mantis 1.0's relaxation is evident with his drastically raised HP stat; it's one of the highest in the metagame, and he can last even longer if he is given ARM by his comrades.
Other than cheap damage, Doom Mantis's long, stabbing appendages are capable of piercing ARM and, with a Yellow Spike boosted Flay, the armor is peeled off the opponent painfully! That's a vivid image I don't want imprinted in my mind. Or my skin, frankly.