Ikkaku is a tall man, whose body is toned and muscular. He is bald, a fact made fun of by many people, especially 11th Division Lieutenant Yachiru Kusajishi, who calls him "cue ball", "chrome-dome", or "pachiko-head" (as a result of her fondness for giving people nicknames or when he questions her direction skills). Ikkaku's bald scalp is very reflective under the sun, which is mistaken for a full moon. His dark-colored eyes each have a small red marking at the outer corner. Ikkaku has a scar, which he while fighting Ichigo Kurosaki during the Ryoka Invasion, running down the left side of his chest. He wears the standard black Shinigami robes, with the exception of no tabi with his sandals and sports a gold-plated shoulder plate on his right arm with the kanji for dragon printed on it.
Ikkaku is violent, fight-loving, and rude, which has been noted by Tetsuzaemon Iba, among others. He is also quite stubborn and cocky at times. He loves fighting so much, he is unwilling to travel anywhere without a sword, resorting to carrying a wooden one when posing as a student at Karakura High School. Ikkaku is very self-conscious about his baldness, often insisting he is not bald, but that his head is "shaven", and will threaten anyone who points this out.
Ikkaku considers fighting fun, and tries to get as much fun as he can, even taking deadly risks to drag out fights for as long as possible. He limits his skills in order to make fights last longer, using his Bankai, or even his Shikai, as a last resort against his opponents. Ikkaku constantly smiles when engaging in a fight with a formidable opponent, much like that of Kenpachi Zaraki, since they have a degree of respect and devotion for each other.
Ikkaku considers the only honorable battles to be those fought one-on-one. Even the threat of death is not a reason to ignore this fact, for he believes the winner is only determined when the other dies. In his fight with the Arrancar Choe Neng Poww, Ikkaku was losing badly, yet refused to surrender or use his Bankai.
Ikkaku has a sense of loyalty and responsibility; refusing to take the position as captain of either the 3rd, 5th, or 9th Divisions, when Aizen and his cohorts defected from Soul Society. He is fiercely loyal to his captain, under whose command he wishes to die. He considers surviving an otherwise lost battle good luck, which his captain taught him, and carries a blood-clotting ointment in the hilt of his Zanpakutō.
Master Swordsman Specialist: Despite being ranked 3rd Seat of his division, his rank does not reflect his fighting abilities. According to Yumichika Ayasegawa, Ikkaku is the second strongest fighter in the 11th Division. He uses a fighting style that is noted at being rough but powerful alongside the use of complex movements that allows him to lunge with his sword from the left and defend with his sheath at the right, though he is ambidextrous and can easily switch between the two techniques. He uses misdirection in his attacks and even though doing so allows for holes in his defense he is more than capable of making it up with surprise attacks. However, his mastery of this skill is great enough that Renji Abarai begged Ikkaku to train him.
- Naginatajutsu Master: Ikkaku's Zanpakutō is a Naginata-type weapon while in Shikai. He fights with this style for longer and more heavier attacks. This helps him combat more proficient swordsman opponents.
- Bojutsu Master: Though Ikkaku's Zanpakutō is a Naginata-type weapon while in Shikai form, it can split apart into a three-sectioned staff and back into a Naginata. While in the split form, he is highly proficient in the use of techniques similar in use to that of bojutsu to take advantage of its versatility for close or mid-range attacks.
Hakuda Expert: Before he became a Shinigami, Ikkaku was always roaming around looking for fights. Most opponents did not have swords, so he frequently fought barehanded. He won against everyone he fought, and upon seeing his strength, most people fled from him. When Moe broke his Zanpakutō, Ikkaku resorted to fighting unarmed, and swiftly defeated the Fullbringer with his level of close-combat.
Shunpo Practitioner: Ikkaku has been seen using Shunpo frequently, though he only uses it to keep up with stronger opponents; this way he can fight more.
Enhanced Strength: Ikkaku obviously possesses a high level of strength, as he was able to block a punch from Edrad Liones in his released state, even when severely injured. Ikkaku sent Hōzukimaru flying several meters away and through solid rock with a single attack. Several of his opponents have commented on the strength of his blows. His muscle control is highly developed, for after having a shoulder dislocated, he reset it by flexing his muscles.
Enhanced Endurance: Ikkaku has been shown to have an incredibly high endurance. In his first fight against the Arrancar Edrad Liones, who had released his Zanpakutō, Ikkaku was losing with ease against an Arrancar even when the he uses his Shikai. Ikkaku is then told by the Arrancar to give up but he fights back and after using for the first time his own Bankai he won against the Arrancar. In another fight with Arrancar Choe Neng Poww, Ikkaku was losing poorly, even his Shikai was completely destroyed, yet he wanted to fight regardless. During his fight against Moe Shishigawara, even after taking several critical hits to the point of coughing up blood, he still fought on and defeated Moe.
Enhanced Durability: Aside from his impressive resilience and stamina, Ikkaku has a great degree of physical durability, able to withstand vicious blows and still continue to fight despite the odds.
Hōzukimaru (Demon Light): It appears like any regular Zanpakuto when sealed. Madarame does hide a small vial of healing ointment in the base of the hilt, though. Hōzukimaru's cross-guard is an oval, with what look like three small teardrops in relief on both the top and bottom end. Hōzukimaru's sealed form enables Ikkaku to employ it in battle as a normal weapon, with its sheath being wielded in his other hand to serve as a secondary weapon.
- Shikai: Its Shikai command is "Grow" ("Extend" in the English Dub). Hōzukimaru's Shikai is unusual in that Ikkaku slams Hōzukimaru's hilt (and sometimes its pommel) into its sheath to activate it when saying the command phrase. Once activated, Hozukimaru takes on the form of what initially appears to be a naginata (spear) with a wax wood shaft. The pommel also has a red horsehair tassel. While able to deliver powerful blows, it is not very durable as it tends to break against particularly strong strikes.
- Shikai Special Ability: Ikkaku uses the command "Split" ("Split Apart" in the English Dub) to separate his naginata into its true form which is a Sansetsukon (Three Sectional Staff), after which the sections can independently reconnect and separate again at will. This special ability surprises one's opponents when they first attack. These chains are also able to extend a fair length, allowing Ikkaku to swing his weapon like a flail for mid-range attacks.
- Bankai: Ryūmon Hōzukimaru (Dragon Crest Demon Light): In Bankai, Hōzukimaru keeps the three-section theme but loses its naginata properties. Instead, it is merely three over-sized weapons connected by an equally large chain. To activate his Bankai, Ikkaku slams the two broken pieces of his Shikai back into the spear-form and says Bankai. Ikkaku's two main weapons are a Chinese Monk's spade and a standard Guan dao. Both have a traditional horsehair tassel at the hilt and a long cylindrical weight for a pommel. The pommels are connected by a heavy chain to the center section, which resembles an axe-like blade with a parallel handle forged into the blunt end and a dragon crest on one side of the blade. Despite all three weapons being of near-ridiculous proportions, Ikkaku wields them easily. Ikkaku usually holds one blade in each hand and lets the central portion "float" behind him, though he will occasionally spin the entire configuration about using the center handle as a pivot. Even though it was repaired by Akon of the 12th Division, Ikkaku's Bankai is still weakened since the fierce titanic battle with Edarad Liones.
- Bankai Special Ability: Ikkaku's Bankai, like his Shikai, is quite unusual. Aside from the increase in strength and power, his Bankai offers no special abilities and no special defensive or Kidō properties. It releases some reiatsu which starts to grow in strength. Ikkaku treats Hōzukimaru a lot different than other Bankai users treat their Zanpakutō (as they just let theirs slumber and use it when they want to do Bankai). But if he forces it to awaken suddenly, cutting the enemy and not getting cut becomes a lot harder to handle than it should be. Thus Ikkaku's Bankai gets increasingly more powerful as the fight drags on. After he performs his Bankai, the dragon crest will slowly fill in with crimson dye as Ikkaku's spiritual power rises. It fills faster when he spins Hōzukimaru with the center handle. Ikkaku comments that his Zanpakutō is actually very lazy in battle (in stark contrast to Ikkaku himself) and needs to be woken up through causing or receiving injury; which would explain its ability to accumulate attacking power the longer the fight extends. When the crest is completely filled, Hōzukimaru is at its full power. However, the force of unleashing so much power can leave his Zanpakutō's edge brittle under excessive stress.
- 11th Division
- Ichigo Kurosaki (Close friend and friendly rival)
- Renji Abarai (Close friend and swordsmanship student)
- Rukia Kuchiki
- Tōshirō Hitsugaya
- Rangiku Matsumoto
- Shūhei Hisagi
- Izuru Kira
- Momo Hinamori
- Karin Kurosaki (Close friend)
- Uryū Ishida
- Orihime Inoue
- Yasutora Sado
- Hanataro Yamada
- Keigo Asano
- Kiba Inuzuka
- Ichigo Kurosaki (Friendly Rival)
- Tetsuzaemon Iba
- Edrad Liones (also enemy)
- Ryuha Armament Alliance
- Sōsuke Aizen
- The Arrancars
- Edrad Liones (also rival)
- The Espada
- The Bounts
- Moe Shishigawara