Renji Abarai is the lieutenant of the 6th Division under Captain Byakuya Kuchiki. Renji has brown eyes and long crimson hair, which is usually kept in a high ponytail. As a child, Renji's hairline was leveled. Later, he styled it in a large widow's-peak. His upper body is covered in tribal tattoos, which have increased over time, starting from his early days as an academy student to covering his entire back, much of his chest, his extremities, and even much of his forehead. He wears a standard Shinigami outfit, though he usually includes some sort of headgear, usually expensive glasses, or a white headband when he is saving up to purchase some new glasses. Despite being of appropriate rank, Renji does not wear his Division's lieutenant badge. While out of uniform, Renji often wears a white kimono-like type of night clothing, with pink floral patterns on it, and a dark grey sash tied around his waist. It has also been said "that the women within his Division do not mind that he usually walks around in his night clothing."
Seventeen months after Aizen's defeat, Renji's hair has grown longer and he wears a maroon colored bandanna covering all of the tattoos on his forehead. He also wears long dark straps on each wrist with bandages over his arms.
Renji is quite dynamic. His personality varies from smug and cocky to disquieted and depressed after a major defeat, but shows himself to be an incredibly serious and determined fighter when confronted with an actual threat. Willing to fight, kill, and die for whatever he believes in, Renji is a dangerous man to those who stand in his way. Yasutora Sado compares his fighting style to that of Ichigo Kurosaki. Renji is determined to surpass his captain, Byakuya Kuchiki, and it's this determination that drives Renji to grow stronger. Renji likes taiyaki (a popular fish-shaped pancake usually filled with sweet bean paste), and has a dislike for spicy food. Renji also likes futsal, and in his free time works on assembling a team from the 6th Division, with success, more or less. The current members are himself, Rikichi, and the 4th, 8th, 13th, and 20th seated officers.
All of Renji's sunglasses are purchased from Seireitei's popular Gin Tonbo store and cost half a year's worth of his pay check. However, every time he wears a pair, they are broken in one way or another. On these occasions, he replaces them with a tied white bandana, until he can purchase a new pair of goggles. His dream is to wear a pair that he himself designed at least once.