Hagane only knows only one rule in life, and that is the bigger things are, the better. For him, strength is everything, strength comes from size, thus size equates to the only factor in a fight. In contrast with this simple logic, he is actually smart enough to use his power to its greatest extent, as shown in the battle with Momiji Satomura where he perfectly rendered her lightning-fast beams useless.
Hagane is Jin Arizuka's follower. His purpose of joining Ragnarök seems to merely due to his wish of proving himself. He called himself an improving genius, but is actually simple-minded. Jin was disappointed about him since he could not think of more than three variations with his battle axe.
Hagane took part in the second battle of Ragnarök, where he first encountered Momiji Satomura and Nagisa Suzushiro. He was able to beat Momiji since her Magic was a great disadvantage against Hagane's power-type Magic. However, when he was about to destroy Momiji's Magic, Nagisa's wish of protecting her best friend awakened her power, enabling her to defeat Hagane with a single blow.
Eckesachs (エッケザックス ekkezakkusu): Hagane's weapon takes form of a gigantic battle axe, seemingly doubled his own size. Each swing of this axe can seriously destroy the enemy as well as the surrounding with a single strike. Of course, because of this, Hagane can hardly combine his attack with his allies. In Kadenz fermata//Akkord:fortissimo, Hagane uses Eckesachs to launch others across large distances. He does this by placing them on the enormous axe and swings them towards their destination. On Day 20, he uses this skill to launch Ayane or Hinako towards Alicia's location.
Gravitonpress (すんげぇ強えぇ重力 （グラビトンプレス） gurabitonpuresu): since Eckesachs' weakness lies in its poor mobility, Hagane was equipped with a gravity Rune that allows him to pin down the opponent until he can strike.
Graviton Naeus (踊り狂う重力力場(グラビトン・ナイオス) gurabiton naiosu; Japanese for "Gravitational Field of Ecstatic Dance"): A more powerful version of Kengo's Irenaeus when combined with Hagane 's Gravitonpress. With super gravity empowering the blades, the attack has more power. Both Kengo and Hagane are seen using this combo rune in Sayuki's Route and in the final battle in Kadenz fermata//Akkord:fortissimo.