He is very loyal and dedicated to Mitsuomi, even suggesting Mitsuomi should use him as a puppet. claiming as long as he has a body he will serve Mitsuomi Mitsuomi seems to trust Shiro a great deal, even suggesting Shiro and Emi will continue to fight for him even after his death. In last years tournament he was the Executive Council's "middle guard", but has been moved to the "reserve" slot for the sake of Emi's strategy.
He is a violent fighter, but does not take pleasure in hurting his opponents. He seeks for strong opponents and feels honored for fighting against them. He is currently ranked 9th of the Todo Academy's strongest fighters.
He is one of the first to pick up on the fact that Aya Natsume's power is starting to awaken. He figured it out just by walking past her. He fears she may become a threat to the Executive Council one day, and wants to eliminate her. Despite the fact he views the Juken Club as a major threat, he holds no ill will towards them. He even assisted them at one point.
Shiro fights with what initially appears to be a staff, in actuality it is a multi-sectioned weapon (like a sanjiegun but with more sections) that he can split apart by twisting the handle. The staff is very durable, capable of smashing concrete without sustaining damage. Tagami's techniques tend to shred the clothing of his opponents, as he hits many times in a short period.
After Aya has an argument with her sister, she goes to the stairwell by herself, Shiro attacks her there. Initially unimpressed with Aya, since she only displays her jujutsu. Aya is unable to fight back as Shiro's staff is too long and she can't get in range. She heads up the stairwell to a narrow corridor before the roof to limit Shiro's attacks to thrusts. Unfortunately Shiro reveals his staff isn't truly a staff; he splits it into multiple sections and the resulting beating shreds Aya's clothing, especially her shirt.
Realizing her disadvantage in the narrow space, Aya kicks out the door and moves the fight to the roof. Tagami removes the bandana from his head and puts it on the end of his staff extending it to Aya to cover herself. He insists he hates an unfair fight such as this, but he must eliminate her before she can realize the power of the Dragon's Eye.
Contrary to Shiro's intentions the fight actually awakens Aya's Dragon Eyes and Shiro is unable to hit her as a result. He notes the eerie feeling of malaise, as if she was mocking him. Even at point blank range he can't land a hit. Eventually he thrusts at Aya but she wraps her hair around the staff holding it in place. He realizes she is able to see everything before it happens, as if he is being made to move. Aya slams him into the ground and takes away his staff, she laughs as if getting enjoyment from Shiro's pain.
As Souichiro Nagi comes up to the roof, he sees Shiro is smashed upside down into the bowling alley's billboard, and appears dead. Aya's still has his staff which is covered in Shiro's blood. Aya is very upset saying she knew his bones were broken, she heard him thinking "please stop", but she couldn't stop herself. She fears she may have killed him. Souichiro humorously calms her down by kicking Shiro in the ribs causing him to gasp, proving he was indeed alive.
After that Shiro is absent from the anime and OVA's, likely recovering from his injuries.
After her encounter with Madoka Mawari, Emi ends up in the hospital alongside Shiro, who is shocked to finally see Emi's true form. Mitsuomi enters, and says he wants the two ready for the tournament, as they are his true wing not F.
As the first round of the tournament starts, Tagami is the only member of the Executive Council to actually show up. He single handedly defeats the opposing team. It's revealed that in last years tournament Shiro was in fact the "middle guard", but Emi placed him as the reserve this year for some kind of elaborate strategy. Shiro dislikes it referring to it as a "taboo" for him. He does however assist the Juken Club since he doesn't like indirect methods. As Masataka Takayanagi over-slept Shiro shows him a short-cut to the battlefield. As the rest of the Juken Club was pinned down, and Emi had made a deal with the Archery Club to hold the Juken Club until the round's time was up, so the Juken club would be disqualified. Emi was displeased, but Shiro insists there is no need to make them take a "useless detour".
Shiro later learns of the plan to destroy all the Red Feathers made by Ichiyo Nagi. This plan is the reason Dogen and Mitsuomi have teamed up, even though they plan to use it for different reasons. While Mitsuomi wants to wipe out all the Red Feathers, Dogen wants to skew the plan to make the "True Warrior", planning to form his own powerful organization around the true warrior. The Executive Council members dislike Dogen as a result, especially Shiro. Shiro even comments he'd gladly kill Dogen when he is no longer useful, despite the dishonor of it.