Lord Garmadon

Lord Garmadon, son of the First Spinjitzu Master, father of Lloyd Garmadon, and older brother of Sensei Wu.
He became evil after being bitten by the Great Devourer in early childhood.
After the venom in his blood fully consumed him following his father's death, he attempted to conquer the world of Ninjago, but was banished by Wu to the Underworld.
He took Samukai's signature helmet and became the ruler of the underworld.
He returned, commanding Samukai's skeleton army, and became the sworn enemy of Wu and the Ninja Team.
Character Abilities:
The Mask of Deception gave Garmadon telekinesis. The Mask of Vengeance gave him four arms and enhanced ninja skills. The Mask of Hatred gave him impenetrable skin, even though it's not made of solidified lava.