Renji Abarai vs. Tetsuzaemon Iba is a brief clash between 6th Division Lieutenant Renji Abarai and 7th Division during the Kasumiōji Conspiracy over their opposing views on how to handle Ichigo Kurosaki's actions during the ongoing Coup of the Kasumiōji.
Ōmaeda is resting outside the 2nd Division barracks, whereupon he is approached by a Shinigami who tells him that the security team is in position, and asks for further orders. The Shinigami is surprised when Ōmaeda tells him to stand down, as there are other Divisions taking action, particularly the 3rd Division. Ichigo Kurosaki questions Amagai's motives in helping them, to which he says that he has his own reasons.
As they run off, two Shinigami from the 7th Division observe Amagai's involvement with the Substitute Shinigami, and immediately leave to report this to their captain. Later, Captain-Commander Genryūsai Shigekuni Yamamoto is informed of the 7th Division's observation by a messenger, and decrees that Amagai must be apprehended at all costs. Lieutenant Tetsuzaemon Iba and his search squad are seen patrolling around Seireitei, as he tells his subordinates that they are within their rights to capture the criminals, as they were the first to see them.
Iba wonders why Captain Amagai would betray the Gotei 13, as he comes across the lieutenant of the 6th Division, Renji Abarai, who has assembled his own search squad. Iba asks Renji why he is here, stating that he's a long way away from the 6th Division's territory. Iba tells him to leave at once, but Renji and his squad merely walk past Iba, as Renji tells him not to stop him. Renji questions Iba's judgement, stating that he knows Ichigo and Rukia better than him. Iba agrees with this, but states that he is under strict orders, and he will force Renji to leave if he has to. Renji then draws his sword to Iba, who does the same, stating that he doesn't need the assistance of his subordinates.
Captains Shunsui Kyōraku and Jūshirō Ukitake walk down a corridor, whereupon they are informed by Shunsui's Lieutenant Nanao Ise that fights are breaking out all across Seireitei. Renji and Iba clash, releasing their Shikai, as they comment upon each other's strength. As Renji moves to attack again, he asks Iba if following orders is so important to him, to which he agrees. Iba and Renji move out to a rooftop, where Renji releases his Shikai once more, extending his Zanpakutō's ligaments, which are knocked back with a single strike from Iba's sword. Iba asks him whether he doesn't care about how this makes him look, to which Renji counters, saying that he is the one blocking his path. Renji tries to plead with Iba once more, saying that Ichigo and Rukia wouldn't do something so reckless without good reasons, as Iba stares emotionlessly at him.
Iba explains that it is not just them fighting, that everyone's Reiatsu was fluctuating. He goes on to explain that Yamamoto's order was the main factor toward this chaos. Renji begs Iba, telling him to let him go, saying that he will prove their innocence. Iba sheathes his sword upon Renji's explanation, stating that he has no choice but to agree with Renji's point of view. Iba tells him that he's not the only one and that most of the Gotei 13 trust Ichigo, but he still has to follow his orders to capture them and bring them to Yamamoto. Iba then asks Renji what he will do if Ichigo really has changed sides, to which Renji says that he will kill him.