His realname is Milliardo Peacecraft. Due to the fact that he felt that his hands had been stained with blood, he felt unqualified to be the successor of the Sank Kingdom. In the past he hid his true identiy in the OZ and did so by wearing a mask. He was known as the "Lightning Count".

The man who would become Zechs Merquise was originally born with the name Milliardo Peacecraft. He was the son of King Peacecraft of the Sank Kingdom, and is also the brother of Relena Darlian/Peacecraft. He wore a mask to conceal his identity while in the OZ organizaiton and is sometimes referred to as the "Lightning Count" for his battle prowess. He regards Heero as a worthy adversary and at one point rebuilds the destroyed Wing Gundam so that they may again battle one day.