Before he was reworked, he used mana. This changed after he's been reworked to energy, similar to Lesley and Fanny, some days before Selena's release into the original server. His skills were also reworked to improve his agility and damage.
Lolita is the other hero whose second bar changed on her current rework.
He is inspired by Ryu Hayabusa who serves as the main protagonist of Tecmo's Ninja Gaiden action-adventure video game series, in addition to featuring as a player character in the Dead or Alive fighting game franchise by Koei Tecmo and Team Ninja.
He is a dragon-human hybrid who wields an ancestral weapon called the Dragon Sword, and is the leader of the Hayyabusa ninja clan.
His main rival is Hanabi while his friend or lover is Kagura as seen in the official web-comic: Intertwined Fate.
The kunais seen on his animation in the hero select screen are not used in the game.
It could be a cutted action from the game, for the shurikens to be used instead.