This is basically onaga koopa's transformation most because it's fused with ogre and oni demon blood he has mixed into his vains, he has a hidden kanji that only appears when he summons it. His kanji is 死 Meaning Death. It only represents that because my evil self hunger's for blood, slaughter, vengeance, revenge, injustice, darkness, fearless and vicious, my alternate evil self doesn't use mercy, he kills without a thought and doesn't like the weaklings that stand before him, or sense them coming even, a blood-thirsty and cold-blooded merciless killer form can not be used mostly because it can be unstable when used too much, unlike bowser, he doesn't care about anything, he has no loyalty or honor, he just loves to kill and stab things just for fun and pleasure.