Half Man Monstrosity (Techpriest/Admech/Skiitari)

From the moment you understood the weakness of your flesh, it disgusted you...

To many biological creatures, you are an abomination who traded his mortality for steel. To yourself, you merely made the logical choice. However, this has left you unfortunately soemwhat screwed in the ways of healing. Potions and healing spells have half as much effectiveness due to your less than human biology. However, this also means you resist most physical damage and some elemental damage as your faith in the surety of iron is rewarded. However, you cannot heal to full through any magic or potion; you must repair your metal parts eventually. Mending can be used for this purpose, but only on one piece at a time. 

You are immune to necrosis and exhaustion and do not need to eat or sleep. You resist non-magical physical damage. You are vulnerable to electrical attacks and acid attacks. You are especially vulnerable to adamantine attacks.