I don't think that's how it works. 120% of "max HP". I don't believe "max HP" accounts for relic boosts or buffs. I think, and I could be wrong, that it only factors the base HP plus any talisman added HP. So, if a viper-wearing toons has +180% HP via relics.. then it'll still be left with at least 60% HP.
So, in order for him to "murder" those talisman wearers, the player would need to not have any relics and not have any HP buffs present such as Oracle or Charlottes HP+, then there are defense shields.....
Basically.. he ain't murdering anyone.
His moves are okay.. for me it's just the fact that EVERYTHING is "single hitter".