Goblin (Juggernaut)
Your arms have Rubilite crystals growing through them, making them harder than most steel.
Your Crystalline Arms are Natural weapons that deal 1d10 blunt damage, with the Reach, Smash, and Modular (Blunt, Electric, Fire, Ice) traits. They gain additional damage dice when you reach 5th (2d10), 10th (3d10) and 15th level (4d10).