|(Current) Final Appearance||Ongoing|
Sebastian is a mysterious German man that agrees to meet with Japanese reporter Seiichi Kikuchi to act as an interpreter.
Sebastian has a plain looking face with a constantly dead-pan expression, a receding hairline and a large forehead.
He takes Kikuchi to the Gantz factory, and later to the mansion of the inventor of the black balls, Heinz Bernstein.
Later, Sebastian draws Kikuchi out of his hotel room and taunts him, asking if something about the "truth" didn't sit right with him. He begins to offer further explanations, stating that Heinz's daughter was simply a receiver for the Akashic records. Then he suggests perhaps reality is simulated, offering The Matrix as an example. His pattern of speech then changes and he asks if God takes a human form.
He instructs Kikuchi to watch as an old lady drops dead, followed by a car crash. After dropping a plane from the sky, Sebastian vanishes with the Gantz teleport method, leaving Kikuchi shocked and horrified.