Weiss is one of two Stygian that were created when an ancient Stygian crumbled through time and obscurity. He traveled through the Nightmare Realm in search of his other half, Schwarz, and restored him to an independent Stygian form by collecting his fragments. Having completed his initial goal, he has ceased wandering and usually resides in his kingdom, though he will leave to travel with Schwarz if his other half wishes to. 

He is quiet and usually keeps to himself, though he is by nature a considerate person and would not harm others unless they get in his way. However, he is very pragmatic and logical, which can veer into cold-hearted ruthlessness at times. It is probably easier to appeal to Schwarz for something (and get Weiss to agree by extension) than to convince Weiss himself. He returns favors with favors and disdain with disdain - while he may forgive, he will never forget.

His preferred weapon is a simple one-handed sword. In lieu of powerful magic, his strength is his precision and agility. He has average defenses, but is difficult to hit with his battle focus and speed.

Usually, he appears in his standard form or human avatar form, and avoids showing off his presence or power. However, he doesn't intentionally conceal his presence unless necessary.