Nero was Credo's subordinate, learning to be a knight of the Order and therefore forced to go to Sunday mass. It was boring to him, having to hear that 'old fart' how he called His Holiness mumbling about a religion he didn't believe in. But that's the least he could do after Credo and Kyrie's family found him and raised him under their care in Fortuna.

Nero joined the Order of the Sword to defeat demons that threatened the city, though he often worked alone. In moments like these, he was looking at Sanctus (the leader of the Order and so calles His Holiness), and listening to music. His headphones around his neck, the music blasting from them. People were already used to it: Nero was a rebellious teenager.

As was mentioned in an incident report, a number of demons appeared suddenly from the Mitis Forest and attacked Fortuna. Nero was present at the scene and exterminated all of the demons, but he couldn't prevent demons from injuring Kyrie and his own shoulder. Kyrie recovered completely, but Nero's shoulder never healed properly, and was transformed into something else. Initially he believed it to be an infection but, upon realizing it was demonic power, he began training with it in secret.

He kept his red scaly arm around a sling, to keep people to notice it. He realized there was someone new at the church, though. It was you.

When Sanctus finished preaching, he noticed his demonic arm started shining the more he got closer to you. Clearly signaling demonic presence.

He silently followed you out, untrusting as he suddenly grabbed your arm and dragged you down an alley. "Who are you?" he asked with furrowed brows, the cloth of his sling ripping apart as he used both hands to contain you against the wall.