Iba has a distinctive hair cut and wears black sunglasses with his standard Shinigami uniform. He collects sunglasses, his main source being "Silver Dragonfly Glasses Store," the same shop where fellow lieutenant Renji Abarai purchases his goggles. He also smokes and carries his Zanpakutō as a small blade inside his uniform. He has a large tattoo on his back consisting of a cat on fire and the kanji shōfuku (inviting luck). These features, plus his informal style of speech, are all strongly reminiscent of a typical yakuza.
Iba is very loyal to his captain, though in the week after Kaname Tōsen's betrayal he spent a lot of time at the Eleventh Division headquarters in order to give his captain some space. Preceding their fight, Ikkaku mentions that Iba has become cockier since he left the Eleventh Division to become a lieutenant. Iba also seems to have recurring stomach problems, which he notes with shame on a few occasions. He and Ikkaku Madarame seem to have something of a working relationship, though it consists mainly of them dueling, drinking sake, then dueling again to see who has to get more.
Not much is known about Iba's Zanpakutō, strength, or general personality. Iba is seen frequently in the company of the other male lieutenants and seated shinigami. He seems to share their pension for perverted things related to the female Shinigami of the Gotei 13. He is also both extremely loyal and decisive, as seen when the Arrancar, Pō sent his captain flying right before unleashing his Zanpakutō, turning into a colossal creature. With his captain briefly sent out of the battlefield, Iba grabbed the injured Ikkaku (his former squad mate) and ran, knowing that even if Ikkaku was in primed shape and the two of them were to take on Pō's released state at the same time, they would never have a chance to survive against someone with immense power to briefly overwhelm a Shinigami captain. His loyalty to both his former and current squads became visible when he refused to abandon Ikkaku just as Pō was about to attack the two of them, ignoring the former's protests and reasoning that Iba has a better chance of surviving Pō's attack if Iba would just let him be; not soon after that when Komamura rise up again to counter the Arrancar's attack, and then telling Iba to not stray by his captain's side, to which Iba immediately complied.
Iba seems to enjoy fighting, like the other members of the 11th division, but unlike many of them, puts his loyalty to his division above his desire to fight, and is not above retreating from battle.
The macho-ist lieutenant presides himself as president of the Shinigami Men's Association and forces all members to dress like him at meetings, including wearing their uniforms and sunglasses in similar manners to his own. His meetings consistently have him as the butt of the jokes of the Shinigami Women's Association, consistently at odds with their vice-president Nanao Ise on their actions and manners.
Iba speaks in Hiroshima dialect, and wants to spread its knowledge more, therefore at some point in the past he started a course on his own expense, but had to close it down in lack of attendance. He currently pens an article in Seireitei Communication's "Guys Corner" titled "The Hiroshima Dialect Seminar Brimming with Macho-ism." His favorite food is okonomiyaki, but only if it is done in Hiroshima style, while he detests the one prepared in Osaka style.
Iba was originally from the 11th Division, but transferred to the 7th Division because getting promoted to lieutenant in the 11th Division was more difficult, if not impossible. It is later suggested that he wished to become a lieutenant not out of personal ambition, but to please his mother. As a result, his former compatriots in the 11th Division look down upon him, as they deem the other divisions weaker than they are. In spite of this, he has a habit of hanging around their division's headquarters. Despite having left the 11th Division, it is clear he still enjoys a good fight, and during his duels with Ikkaku reveals a maniac grin much like his sparring partner.
Though Iba has been seen infrequently throughout the series, we do know that he will try to do the right thing. He tells a dumb lie to his captain directly before Rukia's execution because he knows Komamura is unsure of the decision, and wants to give him time to decide. Komamura sees right through this, but lets it go, understanding it as an act of compassion.
Iba is well-rounded in both swordsmanship and Kidō, only because it made becoming a lieutenant easier.
Expert Swordmanship Specialist: Being a former member of the 11th Division, which specializes in combat, Tetsuzaemon is a highly competent swordsman. He is also known to spar with Ikkaku Madarame, another expert swordsman, regularly.
Kidō User: Because he was working to become a Lieutenant, Tetsuzaemon also became skilled in Kidō.
The name and abilities of Iba's Zanpakutō are unknown, as well as its Shikai command. When sealed, it looks like a tantō, and he usually keeps it inside his Shinigami uniform with the hilt sticking out.
Shikai: In its Shikai, Iba's Zanpakutō extends into a falchion or a large bladed scimitar with a pick-like protrusion a short distance below the tip of the sword. The first times he releases in anime series, it is during his fight with Ikkaku and when he attempts to stop Jin Kariya, but the actual releases occur off-screen. He also releases it in the Bleach movie Memories of Nobody in a duel with Ikkaku. In the manga, he hasn't released it until the Fake Karakura Town Arc, when he attacks Allon from behind, but the command and name is still unknown.
Bankai: Not Yet Achieved
(Source: Bleach Wikia)