Pentakill Mordekaiser's body

Edit: I will completely ignoring the lore retcon. Please do not mention it. Mordekaiser is described as being a living suit of armour. So I can understand the confusion about why exactly Mordekaiser has a human body when he performs in Pentakill concerts. Perhaps he possesses a body when he goes to perform with his fellow band mates? If he possesses bodies while on performances, this could relate to the issue that Mordekaiser lacks an actual, corporeal body unlike his fellow Undead band mates, Karthus and Yorick. I can assume that if he dressed up in his Pentakill attire without a body, he would be mostly invisible to his audience, due to being an animated suit of armour. In addition to the possible visibility problem, another explanation could be how inconvenient it is for the Master of Metal to play "Numero Uno" while in his regular form. Not particularly easy to strum a guitar's strings while wearing metal gauntlets.