Appearing seemingly out of nowhere, his true identity and origin were never discovered. The Joker was a notorious mass murderer, terrorist, and anarchist with white skin, green hair, and red lips with a tendency to wear purple clothing, concealing the true force of chaos underneath his colorful appearance.
' Take a hint, old boy, we may have had our differences, but you and me, we're made for each other.' ―The Joker's views on his relationship with Batman