Koarai is known to be a child prodigy. He is a fairly capable Attacker, having scored over 7000 points with Kogetsu. Although he was noted to be an average fighter on his own, his coordination with Tsuneyuki Okudera is so advanced that they are able to defeat most higher-ranking opponents by teaming up. According to Sōya Kazama, their teamwork at close quarters is second only to his own unit's. Their proficiency extends to aerial combat. Generally speaking, when Koarai and Okudera fight together the latter acts as the diversion and is responsible for engaging the opponent first due to his superior watchfulness, while Koarai deals the finishing blow; however, their teamwork is by no means limited to this set-up, as Koarai is fully capable of trading blows with the target at the same time as Okudera. This is rendered especially remarkable by the fact that Attackers have a harder time than other classes capitalizing on numerical advantage against a single target; in fact, Koarai and Okudera can use the environment and their own positioning to prevent their target's allies from helping them effectively. Their teamwork gave them the upper hand against Shinnosuke Tsuji and allowed them to go toe-to-toe with Yūma Kuga in an airborne battle, although they agreed with Mako Hitomi's call not to engage opponents of his and Kō Murakami's caliber in combat without Haruaki Azuma's assistance.
Koarai's swordsmanship is complemented by decently quick reflexes, which allowed him to dodge a Mantis strike from Masato Kageura and intercept a sneak attack from Tsuji, although, unlike the latter, he was unable to react to Yūma's own incursion. Although he lost his footing twice due to sudden attacks from Osamu Mikumo, on both occasions he managed to react quickly enough not to suffer any damage. Koarai can also be observant in the midst of combat, which he demonstrated when he anticipated Tsuji's attack from Sumiharu Inukai's movements as well as by sheathing his sword either right before or immediately after Yuzuru Ema used the glow from Osamu's Raygust to snipe at him in the dark. After round eight of the latest season of rank battles, Koarai was permitted by Azuma to equip Triggers in the Sub apart from Bagworm and Shield. He chose a Gunner Trigger, possibly Hound. This concession was motivated by Azuma's estimation that his mentees had been able to judge the state of the battle properly.
In fact, Koarai's eye for strategy is steadily improving under the Sniper's tutelage, and his analytical skills applied to the preparation phase of the battle have been refined between his unit's two fights against Tamakoma Second, although his enthusiasm and recklessness still needed to be curbed by Okudera before the start of the second match. Koarai has in fact a reputation for being a gambler in terms of planning, as well as impulsive and reluctant to withdraw even when retreat is the best course of action. However, his willingness to bail out spontaneously during round eight was seen by many as a sign of growth.
Koarai is fairly proficient with Kogetsu, having scored over 7000 points with it. However, he is still severely outmatched by opponents of Hyuse's level of skill, against whom Koarai lost five rounds out of five. Although he is regarded as an average swordsman on his own, his teamwork with Okudera is so refined that together they are deemed capable of defeating most higher-ranked opponents, with Kazama placing their coordination below only his own unit's. The two lived up to the praise by holding the upper hand against Master Class Attacker Tsuji, who is individually stronger than Koarai. Koarai keeps his Kogetsu conjured at all times. He is first seen using it in Chapter 44 (Episode 22 in the anime).
A Trigger that prevents the user's trion signature from being detected by Radar, therefore concealing their position. Koarai may use it in preparation for a sneak attack, dispelling it right afterwards, as well as to meet up with Okudera without being intercepted by enemies. On one occasion the members of Azuma Unit changed the color of their Bagworms to camouflage in a snowy map. Koarai is first seen using it in Chapter 110 (Episode 67 in the anime).
Koarai uses this Trigger to defend himself while approaching Gunners and other mid-ranged combatants from the front. He seems to prefer casting it in its default hexagonal shape, making it big enough to protect his midsection and most of his head and legs if he crouches down. Koarai is first seen using Shield in Chapter 113 (Episode 68 in the anime).
Koarai rarely utilizes this Trigger as he appears to prefer to close the distance with the opponent, especially if Okudera is close by. However, he will resort to it to cut down an enemy who tries to escape. Koarai is able to synchronize his slash with Okudera's. He is first seen using Senkū in Chapter 172.
Although this Trigger is not part of Koarai's normal set, he often adds it to improve his mobility on certain maps while the terrain makes movement on foot unfavorable for his opponents. He can also use it to cut off an enemy and trap them between himself and Okudera, or more generally to control his position while airborne. The two Attackers are skilled enough to briefly hold their own against Yūma in an aerial battle. Koarai is first seen using Grasshopper in Chapter 168 (Episode 68 in the anime).