It’s unlikely that Necronumos was called by that name as a child, but no one (no one alive at least) knows him by any other name. He was an especially strange child with an unsettling fixation on death. Nobody in his village liked him, not even the dogs and cats, which was a shame as he had a keen interest in both people and animals. In particular, he was interested in what they were like on the inside. Literally, he wanted to know more about their innards.
It all started with insects, beetles and spiders, then progressed to fish, frogs, mice and birds. Pets and livestock were even more fascinating to cut open and explore, but he couldn’t poach many of those without raising suspicion. What he needed was an abundant supply of dead things that no one would miss. Late one night, he paid the first of many visits to the village cemetery.
Before long, merely examining the dead wasn’t enough, and Necronumos began experimenting with dark, necromantic magic. He had an unnatural talent for it, and soon the first “recruit” for his Undead army was reborn. Before long, the whole graveyard was under his command and he had to expand his recruitment drive to candidates who weren’t yet dead.
Now, every inhabitant of Necronumos’ village is a walking corpse under his command, and he’s selected the best and most rotten of his minions to join him in the arena tournaments. But Necronumos doesn’t discriminate. Any Champion from any Origin can fight for him and, thanks to his cursed taint, will have an improved chance of delivering critical hits. What’s more, he can also perform a little bit of light necromancy on-the-spot, meaning that every Champion fighting under Necronumos gets resurrected as a zombie as soon as they’re killed. It’s not a glamorous way to make a comeback, but in close-fought battles it can make just enough of a difference.