Merlin

In the Kriegszeit System, he was known as Ludwig, and was Star's father. He left, allegedly so Star wouldn't feel forced to follow in his footsteps. He returned, was driven off, and made to return again with a subsystem containing only himself and Rudolf von Stroheim. Dio was forced to kill them both to protect Roderich in late April of 2016. A week later, a way to separate subsystems was discovered.

Solas found him in March 2018, in a fantasy medieval England, as Merlin of King Author's court. After a few visits, it was decided that it would be best to let him live the life he currently leads in peace.