Zastory, River

リバー＝ザストリー

River is, among other things, a Sweeper interested in capturing Creed. He is trained in the Gerbell Command style, a martial art developed in Talica during a thirty-year war. The Gerbell Command style emphasizes extreme power and speed in the fists, sufficient to deflect bullets and generate shockwaves for ranged attacks. Among River's abilities, Sonic Fist and Tornado Grenade are fairly relevant. While Sonic Fist allows River to move his fists in a specific direction, enabling him both to defend (by deflecting projectiles such as bullets) and to attack (as he does against Preta Ghoul, by moving his fists so fast that he creates shockwaves in the air), Tornado Grenade allows River to gather a spiral wind mass around his hand or arm, creating a small version of a tornado, which he uses, for example, to piledrive massive amounts of rock.
River first appears at a local Sweeper Bar that Train and Eve head to (Sven isn't present with them as he's doing his own training to perfect his Vision Eye). After discovering Train's identity, he requests a duel against Train to see if he can beat Train with his fists. He admits defeat after being grazed by one of Train's bullets and seeing his Rail Gun (to which River says even he couldn't deflect). After the boat incident when landing on Kraken Island, where all the sweepers get separated, he ends up in the same part of the island with Train, and they both tag against Preta Ghoul and Maro afterwards. River also helps Train in the fight against Shiki, by fending off the giant insect Shiki summons, while Train takes care of Shiki. Train addresses him as "Thunder head", as his hair is shock yellow. Later on in the manga, River also aids Train in the fight against the berserkers (which're presumably members of the Sweeper Alliance): Touma and Mundock. After the battle, he requests Train to head up to beat Creed.