Andreas would do anything to protect his lady, Claire, and would punish anyone who hurts her. He uses a pair of long blades for weapons, but prefers to avoid unnecessary violence. He seems to have some sort of affiliation with Karasu Tengu, though the extent of which is unknown. He greatly resembles Gino Weinberg.
Andreas appears after the assault on Renya's village, collaborating with the Three Brothers. He watches on as Renya fights the Three Brothers until one of the brothers recklessly throws his weapon around the room, nearly hitting Claire. He then intereferes and impales him with his own weapon.
Afterward, he fights with Renya until he notices the aforementioned brother attempting to take Claire hostage. He tries to stop both him and Renya, but Renya kills the brother in a roundabout way, to his surprise.
Immediately after, the roof collapses and a mysterious individual with power over wind appears and Andreas reveals that this person is a Knightmare. The Knightmare flees with Claire in hand and Andreas gives chase alongside Renya.
However, along the way, they encounter a young woman running from a wild boar, which Renya kills. The woman reveals herself to be Futaba Sumeragi and announces her intention to kill Renya for assassinating Isshin Sumeragi. During the following battle, Andreas interrogates a young man who was with Futaba who reveals himself to be Denshichirou and asks for their help in defeating a demon that can manipulate wind which he calls Karasu Tengu. Overhearing this, Futaba runs off in search of Karasu Tengu's power in order to use it to kill Renya.
Andreas is intelligent and generally good at speaking Japanese but has frequent grammatical errors in his speech (which is a running gag in the story, since this usually happens during critical or serious moments in the manga).
Andreas possesses a strong and fast body with quick reflexes and sharp senses. It was shown that he could change the trajectory or the ballistics path of a thrown weapon or of an arrow by using physical means. He could also endure pain to a certain degree, having to use his hand to receive a knife stab.