鬼丸 [onimaru] in Japanese. 'Oni' is a type of a Japanese demon, while 'maru' is a word often attached to the names of swords.
Mobius

Onimaru
Stats: ATK +30, Break +25, Critical ★, DEF ★
Auto Abilities: Attack raises Limit Break gauge, Drive Heal: Restoration 4%
Obtain: Samurai job card skill panel #2-1
Cost to obtain: 2 Crystal
Type: Warrior Weapon, Rarity: ★
Onimaru+
Stats: ATK +60, Break +35, Critical ★, SPD ★, DEF ★
Auto Abilities: Attack raises Limit Break gauge, Drive Heal: Restoration 4%
Obtain: from Onimaru with Samurai skill panel #2-2
Cost to obtain: 3 Crystal
Type: Warrior Weapon, Rarity: ★★
Other: 鬼丸+ in Japanese
Onimaru+2
Stats: ATK +85, Break +45, Critical ★, SPD ★, DEF ★
Auto Abilities: Attack raises Limit Break gauge, Drive Heal: Restoration 4%
Obtain: from Onimaru+ with Samurai skill panel #2-3
Cost to obtain: 4 Crystal
Type: Warrior Weapon, Rarity: ★★★
Other: 鬼丸・改 in Japanese
True Onimaru
Stats: ATK +110, Break +55, Critical ★, SPD ★, DEF ★
Auto Abilities: Attack raises Limit Break gauge, Drive Heal: Restoration 4%
Obtain: from Onimaru+2 with Samurai skill panel #2-4
Cost to obtain: 99,999 Earth Seed
Type: Warrior Weapon, Rarity: ★★★★
Other: 真・鬼丸 in Japanese
Category: Equipment