Äs is a minor antagonist from the series Bleach. He is an Quincy and a Sternritter within the Wandenreich led by Yhwach and granted the Schrift, F the "Fear". Prior to joining Yhwach, the only thing known of his past is he was bedridden in a hospital after an unknown incident.

Äs has long, black hair and dark eyes with visibly light pupils. His attire is a variation of the Sternritter's typical white uniform, consisting of the order's signature hooded cloak, an ankle-length trench coat with many buttons on its front and sleeves, and black boots. He wears a dark mask, which obscures the lower half of his face and features five spikes running down its center. Beneath his mask he lacks lips and has exposed teeth.

As a Quincy he can manipulate surrounding reishi to enhance his abilities and using his given power, the Fear, he an invoke overwhelming anxiety and fear in his opponent through contact using projectile thorns of pure reishi or other methods. He also possesses a Vollstandig form, Tatarforas, enhancing his ability further where just the mere sight of him gives the same effect to his opponent. His form changes to that of what looks like a zombified version of himself, sporting purple barbed halo and circular wings made of reishi. In that form he's capable of transforming in monstrous ways to further invoke fear in his opponent.