You are missing a hand or part of your arm, and your stump is capped in iron. You cannot wield two weapons at the same time or two handed weapons. You can defend yourself from combat maneuvers, gaining a +2 to your CMD. You can specially mount a one handed melee weapon or a shield (except tower shields) to your stump, allowing them function normally.

Curse Skill: Intimidate.

Adaptive Feats: You gain the following feats at the indicated levels, even if you do not normally meet the prerequisites.
At 2nd level, you gain Improved Shield Bash as a bonus feat. This feat also applies to your stump.
At 8th level you gain Vital Strike as a bonus feat.
At 14th level you gain Bashing Finish as a bonus feat.
At 20th level you gain Crippling Critical as a bonus feat.

Discipline: You have mastered your curse and gain the following abilities.
At 4th level, you can use your iron clad stump as a primary natural weapon. You can make a slam attack that deals 1d6 damage plus your full Strength modifier. Your stump also doubles as a buckler.
At 10th level, the bonus to your CMD increases to +4.
At 16th level, the damage from your slam attack increases to 1d8.

Revelations: Your curse grants you the following revelations.
At 7th level, you gain the Iron Weapon revelation from the Metal mystery, except its effect applies only to your slam attack.
At 15th level, you gain the Clobbering Strike revelation from the Stone mystery, except its effect applies only to your slam attack.