Diamondhead is one of Ben Tennyson’s most iconic alien forms in Ben 10. He’s a tall, humanoid alien made of living crystal—sharp-edged, faceted, and reflective—giving him a tough, “gemstone warrior” look. Diamondhead is a Petrosapien from the planet Petropia, and his body is essentially a super-durable crystalline structure that can take heavy hits and keep fighting.

His powers revolve around crystal control and brute strength. Diamondhead can generate and shape crystals from his body—forming blades, shields, spikes, and projectile shards—making him both a strong close-range fighter and a dangerous long-range attacker. He can also regrow damaged crystal parts and use his hard, angular limbs for powerful strikes. While extremely resilient, he can be threatened by attacks that specifically shatter or destabilize crystal (like certain sonic vibrations or specialized energy effects), and very heavy impacts can crack him if sustained.

Overall, Diamondhead is often used when Ben needs a mix of defense, crowd control, and heavy-hitting offense, with a cool, confident “crystal tank” vibe that fits high-stakes battles.