Rorschach is a vigilante "hero" who relentlessly and mercilessly fights the "evil" he sees in the world. He is a shrewd and dogged (and obsessive) investigator, and brutal, psychotic administrator of vigilante justice. As a result, Rorschach is the most feared (and loathed) masked hero in the Watchmen universe.

Walter Kovacs was the abused son of a prostitute – the multiple psychological traumas he endured as a youth caused him to experience a psychotic break, from which he emerged as the fearless, ruthless vigilante Rorschach. Rorschach has an absolute belief in good and evil, and feels neither pity nor compassion for society's "scum" – including prostitutes (like his mother), pimps, petty thieves, and bullies in general.

Rorschach's identity is the psychological key to his power over his enemies. Without his mask he remains lethally brutal and capable, but the mask helps him to strike fear instantly where his face earns only ridicule and dismissal.

Rorschach's mask is made from an unwanted dress whose fabric consists of black and white liquids trapped between two layers of latex. Pressure and heat cause the two liquids to shift to form symmetrical patterns similar to that of a Rorschach inkblot test. Rorschach obtained the dress while working as an unskilled garment worker. The unique fabric was one of the many innovations of Doctor Manhattan's.

Rorschach has partnered with both Nite Owl and The Comedian, and feels a fierce loyalty to both men, even though he opposes "super-groups" in general. Due to his brutality, dark personality, and the stench of his outfit, Rorschach is not well liked among the other heroes. He is the one hero who defied the Keene Act of 1977 and chose to continue his crimefighting illegally.

• The character of Rorschach is based loosely on the comic-book superheroes The Question and Mr. A.
• Rorschach enjoys chewing on sugar cubes.