Sosshi

Sosshi approaches danger with the survival instincts of a professional mercenary rather than the self-sacrificing ideals expected of a hero. When confronted by monsters vastly beyond his squad's capabilities, he is willing to plead and display fear if it might keep him alive. He is self-aware enough to recognize the indignity of the situation rather than pretending that fear does not affect him.

He is also a capable actor. After experiencing supernatural mind control, Sosshi proves able to imitate the behavior associated with it, a useful talent when the group later attempts to move through hostile territory by deception.

Sosshi is an experienced combatant proficient with swords, daggers, and unarmed fighting. His close-quarters style makes substantial use of kicks, giving him offensive options after his weapons are lost.

His most important equipment is the advanced battle suit supplied to Narinki's mercenaries. The armor dramatically enhances the wearer's physical abilities and has a higher-output state that allows the squad to pressure Iaian, Okamaitachi, and Bushidrill, three of the Hero Association's strongest A-Class fighters.

Sosshi joins Narinki's privately funded mission after the wealthy Hero Association sponsor loses patience with the official effort to rescue his son. The mercenaries enter the Monster Association base and initially defeat weaker monsters, but quickly discover that their expensive equipment does not put them on the level of the headquarters' stronger inhabitants.

G5 captures Sosshi and the other mercenaries during their attempted withdrawal. Do-S subsequently places them under mind control and uses them against Atomic Samurai's disciples. The swordsmen eventually incapacitate the mercenaries without killing them, and Do-S's control is broken after her defeat.

Sosshi continues through the headquarters alongside the freed mercenaries and heroes. Evil Natural Water later overwhelms their group, while Pig God helps evacuate the wounded during the destruction of the underground base. Sosshi subsequently suffers the loss of an arm when Fuhrer Ugly catches him on the surface.

Later in the manga, Sosshi and the surviving former mercenaries work as security guards at Narinki Park in I-City, where they become witnesses to Sweet Mask's battle with Pesky Clown.

Tongara is Sosshi's captain and the leader of Narinki's Private Squad.

Noria, Asami, Chinpi, Sanshon, and Gomago are his fellow mercenaries.

Narinki hires and equips the squad to retrieve his son.

Do-S enslaves Sosshi and the rest of the squad with her mind-control ability.

Iaian, Okamaitachi, and Bushidrill fight Sosshi while he is under Do-S's control and later help save the mercenaries rather than allowing Sweet Mask to kill them.

Ikemen Kamen Amai Mask becomes significant to Sosshi again later when Sosshi publicly recognizes him during the confrontation with Pesky Clown despite Sweet Mask's altered appearance.