Birthdate::November 9th
Gender::Male
Best Friend::Yumichika Ayasegawa
Position::3rd Seat of the 11th Division

Zanpakuto Shikai: Hozukimaru
Bankai: Ryumon Hozukimaru

Seiyu (Japanese) Nobuyuki Hiyama
Voice actor (English) Vic Mignogna

History
Not much is known about Ikkaku's history, but it's likely that he has been in the 11th Division since becoming a shinigami. The anime is much clearer about this; Ikkaku becomes a shinigami after hearing that Kenpachi had become the captain of the 11th Division. During Renji Abarai's time in the 11th Division, Ikkaku was Renji's senpai and taught him how to fight.

Like Rukia Kuchiki and Renji, Ikkaku came from Rukongai. At some point, he met Yumichika Ayasegawa and the two became friends. They would later have an encounter with Kenpachi Zaraki and Yachiru Kusajishi before they entered Seireitei. Kenpachi and Ikkaku fought; Kenpachi easily defeated Ikkaku and nearly killed him. When he asked Kenpachi why he didn't kill him, Kenpachi replied that if he killed Ikkaku now, he would never get another opportunity to fight Ikkaku again. He then told him not to seek death, but to consider himself lucky for not having died. The encounter is Ikkaku's main reason for staying in the 11th Division, as he wants to continue serving under Kenpachi and might not get a chance to fight him again otherwise.