Obsidian Prison Technique

Obsidian Prison technique: The user makes a prison of obsidian that surrounds an area of their choice within range. This Prison forms over the specified radius, can withstand 75 points of damage before breaking and any who are in the area will be shredded by the obsidian moving and cutting at the targets inside while they are unable to escape. Any attempt to attack the prison walls will deal 10 points of atomic damage to the attacker if they make physical contact with the wall. Rank: C. Style: Kekkei Genkai. Chakra cost: 30 per round. Range: 60ft cube, +20ft per round Save: 12, dex vs grapple. Damage: 3d10 atomic per round. Focus: Yes. Requirements: Two free hands. Enhancement: Doubled range. Minor action