What's The Deal With Dead Man's Plate

Who was he...? How did he die? Why is his armor magical?

One of the few items to have text with it, and that's it. Can we pleeeease get some cool backstory about this item. Like maybe it was Hecarim's armor when he was alive, working into the whole movement speed for damage niche, or maybe a champion we don't know about is gonna be resurrected from the dead and have the armors ability as a passive or something but whoever came up with the item reveal yourself and lemme know some details pretty please.