Rakshas is an apostle and assassin in Berserk. He was originally a member of the Bakiraka, an assassin clan serving the Kushan Empire, but was exiled from the clan at some point in the past. Following his exile, he became a member of the New Band of the Hawk, serving Griffith as one of his most dangerous agents. In appearance, Rakshas is almost never seen clearly. His entire body is concealed by a black cloak and a masked face that seem to appear and disappear like a shadow, allowing him to blend into darkness and move without being noticed.

Rakshas is a hedonistic killer. Unlike the disciplined Bakiraka, who treat assassination as a duty, Rakshas treats it as a source of personal pleasure and even performance art. He plays with his victims before killing them, a practice considered heresy within the Bakiraka. He speaks in clipped, arrogant sentences and is demeaning toward anyone he considers beneath him. His driving desire is to possess beautiful things by killing them, regarding the act of taking a life as a way of capturing beauty permanently. This motivation shapes his relationship with Griffith. Although he serves as an assassin under Griffith, Rakshas openly intends to kill him eventually, stating that he serves Griffith only until he can take his beautiful head. He acknowledges that all apostles are enthralled by Griffith, and his urge to possess what he finds beautiful extends to Griffith himself.

Rakshas plays a notable role in the Millennium Falcon part of the story. He acts as Griffith's agent against the Bakiraka, luring them into a trap at a man-made beherit. During Griffith's plan to rescue Princess Charlotte under the guise of an attack on Wyndham, Rakshas confronts Silat and two tapasa warriors, dodging their attacks. He later attacks Rickert after Rickert rejects Griffith's offer to join the New Band of the Hawk, nearly killing him before Silat intervenes. His key relationship is with Silat, his fellow Bakiraka and archenemy. Silat knows Rakshas well and describes him as relentless when chasing a target. The shadowy nature of his background means much of his past remains unexplained.

In combat, Rakshas is formidable even among apostles. He can transform his body, merge with shadows, and move at superhuman speeds. He uses tentacle-like appendages and can generate bladed limbs to slice through targets. When he releases his true apostle form, he gains the ability to fly, and his tentacles become far stronger and more dexterous, allowing him to smash through the roof of a house or lift a horse into the air with a single appendage.