Lucius was raised in a tiny village ridden with poverty. His mother was barely ever around, yet he and his father developed a close bond when he was little. When the village's leaders arrested his father for high treason, he left Lucius the blade Umbra, which he'd kept ever since. The following day his father was executed.
Lucius took to the streets shortly after, training with his new blade and taking "odd jobs" for money, usually involving thievery or assassination. Eventually he began to discover his abilities in Chakra manipulation, forming signatures in both Light and Darkness. He left the village and all human habitation after a while, in an effort to hone his powers.
He made his way eventually to the Nightmare, where he quickly became fond of the Sannin Zeik Hellgate. Zeik took Lucius in as his apprentice after long, and Lucius's progress and skill only grew. It wasn't long before he was offered one of the only Anbu positions in Zeik's new village, the Kingdom of Chaos.
Serving there under Zeik, doing his best to defend the village with his Royal Guard, Lucius began to take interest in what his blade actually was. Through the help of Akarui Yami, he discovered Umbra's powers as a Zanpakuto, a weapon for Shinigami. Around this time Zeik was killed by Hao, and it didn't take long for depression to fully sink in.
A year has passed since those events, and Lucius has become slow and idle. He lounges about mainly in his home, barely speaking to anyone or tending to the Guard. Thing look pretty bad after the passing year...