Birthdate: October 26, 458 R.C. (767 U.C.)

Oskar von Reuenthal is a rear admiral serving in Reinhard's fleet and, along with Wolfgang Mittermeyer, Reinhard's ablest field commander.

Reuenthal was born to a lowly, but rich noble father and a mother from a distinguished but impoverished line that only married his father for his material affluence. Reuenthal was born with a rare condition called heterochromia, one of his eyes is blue, while the other is brown. Since both his parents had blue eyes, this was seen as proof of his mother's adultery. His mother committed suicide after trying to pluck out his brown eye while he was still an infant. Reuenthal's father put the blame on him and he grew up hated and neglected.

Reuenthal joined the military and rose through the ranks rather quickly, finding in war the reason he needed to keep on living. While stationed in fortress Iserlohn, he met Wolfgang Mittermeyer and the two became close friends. Mittermeyer is probably the only person Reuenthal has managed to have a normal relationship with and he greatly values their friendship. When Mittermeyer was unjustly detained and in danger of assassination by the nobility, Reuenthal didn't hesitate to pledge his loyalty to Reinhard in return for his help with Mittermeyer's case.

Reuenthal appears calm and composed on the outside, he is a brilliant war strategist, second only to Reinhard, and an accomplished tactician, but Reuenthal is, in reality, a ticking bomb ready to go off at any moment and perhaps would have already exploded if not for Mittermeyer's soothing presence in his life. His problematic childhood has ridden him with an incredible amount of self-loathing and a complete inability to trust women, though handsome and successful with the opposite sex, he never manages to get into a healthy relationship. Proud and ambitious Reuenthal often contemplates treachery, but his respect towards Reinhard and the debt he owes him, manage to restrain him. His flagship is the Tristan.