AKA Older Zombie Man
After several wars and battles left him partially destroyed more than once, the ever-evolving culture and technology of the Herbal Kingdom gave it's rulers the oportunity to advance one of it's most prominent protectors and family royal.
Using special liquid that pumps from his tanks, Zombie Man regained his thinking ability and became capable of speech and reason. Due to the lack of supplies of spare limbs, King Bit, the Spring Song, improvised and designed a steam-powered metal arm and leg that heightens his strength.
Despite his horrid appearance, he's a well loved warrior under the Herbal Royal's arms, and a beloved "uncle" of the kingdom's young pricnesses...
Adventure Time (c) Pen Ward