Renji is about as eccentric as any other Soul Reaper. He varies from smug and cocky in his first appearances to depressed after his major defeats, but shows himself to be an incredibly serious and determined fighter when confronted with an actual challenge. Willing to fight, kill, and die for whatever he believes in, Renji is a dangerous man to those who stand in his way. He's also one of the only Vice Captains to achieve bankai. Many Bleach fans speculated that he's the most powerful Vice Captain and non-captain position in the Soul Society. He is similar to Ichigo Kurosaki in many aspects, and the two are mistaken for brothers in the anime's Bount arc. Ichigo claims they are cousins to keep things simple, allowing many hilarious situations to occur later, including comments over their unusually colored hair. A continuing gag in the series is Renji's nick name, red pineapple, referring to his crimson hair kept in a pineapple top-like ponytail. During a filler arc before the invasion of Las Noches, Renji wears a shirt with 'Red Pineapple' printed on the front, supposedly bought by Ichigo Kurosaki as a joke. He's even referred as "Aka Pine" during the Shinigami Cup segments.