Sumeragi Ryouta (住良木 良太, Sumeragi Ryouta?), known as Sumeragi (スメラギ, Sumeragi?) in «ALfheim Online» (ALO), is a game-original character featured in the game adaptation Sword Art Online: Lost Song. Sumeragi's ALfheim Online avatar is an Undine. He wields a katana that he can brandish with one arm due to his strength. He has created his own Original Sword Skill, «One-Handed Tyr».