Yoneya is a powerful Attacker who has reached Master Class with two different Attacker Triggers: his customized Kogetsu and the Scorpion, which he currently does not use. He never learned from a single teacher, but increased his skills through continuous fighting. By his own estimation, he would win as much as he would lose in a match against Shun Midorikawa. Unlike the latter, however, he survived through all of Aftokrator's invasion, despite taking parts in multiple battles against humanoid Neighbours. Much to Mikumo's surprise, he was able to anticipate Yūma's movements during their fight. Thanks to his Triggers, he fights at a distance that is often troublesome to the opponent, as it is neither close nor mid-range. He is also adept at forcing the opponent to follow his preferred pace. His innate battle sense and creativity in tactics have allowed him to reach A Rank despite possessing a low trion level. He also seems to possess very fast reactions, dodging Mira's surprise attack without having no info on it and changing the shape of his spear twice mid-swing. His head-first personality belies the ability to quickly adapt and create tactics in the midst of combat. Yoneya is also rather analytical, seeing through Kuga's strategy of pulling Midorikawa into a false sense of security and rapidly finding multiple ways to circumvent Hairein's and Koskero's Triggers. even after receiving a fatal wound from Ai Kitora, he was able to think outside of their duel and change the tides of the battle by pushing her out of the window to be killed by Izumi.
A variation of the normal Kogetsu that consumes less trion, Yoneya is very skilled with it. He has a very flexible fighting style, easily switching from holding the spear with two hands and jabbing at the opponent with the tip in quick succession to using only one hand and slashing at them.
Yoneya regularly employs Gen'yō as part of his combat style to change the tip of his spear. He uses it to hit dodging enemies or ones that attempt to block his attacks. He is skilled and fast enough to activate this Trigger mid-swing and deactivate it immediately afterwards, which prevents his opponent from understanding how it works. He is generally unable to inflict lethal damage on a watchful foe, but it proved to be very effective when targeting limbs.
Thanks to his speed, Yoneya can deliver multiple slashes with this Trigger in a short time. He was able to strike five times within the same activation, although it is unknown if he prolonged it and if his modified Kogetsu gives him an advantage in that regard.