As a member of a unit with a stable standing in the upper tier of B-rank, Oki is a capable Sniper. Osamu Mikumo listed him as one of the three fighters to watch out for during round six, with the likes of Tatsuhito Ikoma and Kazuaki Ōji. He is confident enough in his abilities to think that he would be able to snipe Yūma Kuga and to take aim and fire at Chika Amatori within such a small interval after her own shot that she would be unable to defend. Despite his proficiency, Oki is unable to hit foes as agile as Yūma or Ōji after his position becomes known, although he was willing to try against Yutaka Kashio. Apart from picking off opponents, Oki's contributions to his team encompass suppressive fire and counter-sniping. He is also responsible for discovering the identity of the owner of a trion signature and, when possible, to keep track of Bagworm users, exploiting the vantage points he can reach more quickly than most Snipers thanks to Grasshopper. The above-average mobility this Trigger grants him might be connected to his apparent reluctance to change position after every shot, as it allows him to keep away from pursuers over short distances; nonetheless, he will move to improve his chances of catching the target unawares.
While this approach to sniping can cause him to be tracked down with relative ease, Oki is adept at remaining undetected if the circumstances call for it. His aptitude for stealth was compared to that of the notoriously elusive Kazuto Tonooka during round eight. Switching targets to the enemy Sniper, whom he successfully forced to bail out, was regarded as an astute move, as not only Oki took the danger of losing sight of Tonooka into account, but he also surmised that his previous targets would not give him an opening. Albeit advanced, his ability to analyze the outcome of a shot by factoring in the target's reaction time, distance and muzzle velocity is not flawless, as Yūma managed to survive his pickoff attempt, although he still lost an arm. Oki's knowledge of Border Triggers is extensive enough for him to have developed a tactic to avoid Hound, as well as to recognize Hornet when it fails. His ability to survive the long-distance barrage unscathed, however narrowly, also vouches for decent reflexes, adaptability, and speed at switching Triggers.
Although Oki claims to struggle to snipe younger girls, the veracity of his sentiment is disputed by anyone he expresses it to, and in fact he is willing to shoot; contrary to his assertion, his failure to take out Chika in round six was attributed to his loss of focus when she unexpectedly opted for a mutual hit.
|Kōji Oki's Triggers|
|A Trigger which prevents the user's trion signature from being detected by Radar, therefore concealing their position, and a fundamental asset to Snipers. Oki's Trigger Set is structured so that he does not have to deactivate Bagworm to use Sniper Triggers or Grasshopper, although this comes at the cost of equipping only two rifles in the Main. He dispels the cloak exclusively when pressured into defending with Full Guard. Oki is first seen using Bagworm in Chapter 150.|
|Eaglet appears to be Oki's preferred Sniper Trigger. With it he was able to shoot off Yūma's arm despite the Attacker's incredible reflexes, which saved him from what would have otherwise been a lethal headshot. When Kazuki Kurauchi was similarly propelled with Grasshopper, Oki only managed to injure his shoulder, possibly due to needing to aim and fire quickly. Oki is first seen using Eaglet in Chapter 150.|
|Oki uses Grasshopper to rapidly scale tall buildings and get in sniping position, as well as to swiftly cross the map, whether to take his next target by surprise or to escape a pursuer. In the latter case, the Trigger is not as effective over longer distances, but the initial lead can facilitate reuniting with his teammates. Oki has shown enough skill with this Trigger to summon two pads consecutively, activating the second before the acceleration from the first decreased enough for his trajectory to turn into a parable, signifying a change of direction at high speed. He is first seen using it in Chapter 152.|
|Oki utilizes Lightning for suppressive fire, pinning a target on whom he does not have a clear line of fire on into position and preventing them from assisting their allies thanks to its high rate of fire. Despite the surprise of Chika attempting a mutual hit, he was accurate enough to force her to attempt to dodge, severing her leg in the process. Oki is first seen using Lightning in Chapter 157.|
|Oki appears to prefer to cast Shield in its default size and hexagonal shape. He can cast his two Shields at different distances to intercept bullets coming from different angles while remaining on the move. His sense of positioning is keen enough for him to block part of Masataka Ninomiya's Hornet and get away unscathed, albeit narrowly. Oki is first seen using Shield in Chapter 190.|
|Oki swapped Lightning for Ibis in preparation for his unit's match against multiple opponents with high trion, counting on the surprise factor and the rifle's high firepower to break through the unfocused Shield they could deploy to guard against other Sniper Triggers. He successfully used Ibis to force Tonooka, whose movements were predictable as he was jumping off a building, to bail out. Oki is first seen using it in Chapter 186.|