Toxic Substance

Garou and Bomb trade blows on even footing. Fubuki tries to join Bomb against the Hero Hunter but cannot track their speed, and when she loses focus Garou aims a strike at her. Bomb blocks it and knocks Garou away to keep her clear, then charges after the monster to pull the fight from her. Pig God appears beside Fubuki, notices the gravely wounded Tanktop Master, and is asked to help heal him.

Nearby, other heroes and the Council of Swordmasters keep battling waves of Black Sperm duplicates. A giant Black Sperm clone erupts from the ground to crush Tatsumaki, but Genos arrives and incinerates it. When a second clone slams him into the earth, Genos activates his suit's burial-escape function, built from data on his fight with Tatsumaki, and rises at once. He and Tatsumaki ready themselves against Black Sperm.

Fuhrer Ugly storms in demanding to fight Silver Fang, whom he blames for his ruined body. Mocked by Black Sperm, he spits acid that melts several clones. Superalloy Darkshine strikes with his Superalloy Double Bazooka, but Fuhrer Ugly's Forearm Melting Punch cancels it, and the acid begins eating his own hands. He then slams acid into Darkshine's chest, dropping the hero to the ground in agony. Zanbai warns the others not to attack Fuhrer Ugly unarmed and charges with a sword, only for the blade to melt; Fuhrer Ugly spits acid through his head and kills him. Atomic Samurai and Nichirin strike together with the Atomic Slash and the Iai Rahu-Ashura Slash, but their swords dissolve on his body and leave him unharmed.

Elsewhere Bomb keeps pace with Garou while noting his sudden growth and newly fused style, wondering if monsterization is the cause. Outmatched, Bomb resolves to survive until Bang comes and readies a concealed technique, striking the ground to unbalance Garou, only for Garou to read and counter it perfectly and floor him with one hit. Bang arrives just as his brother falls. Bomb warns him of Garou's remarkable progress, and Bang steels himself to face his former disciple.

Viz Media publishes the chapter as Deleterious Substance, and it partly adapts webcomic Chapter 71. The cover features Tatsumaki, Saitama, Blast, Flashy Flash, and Manako. This is the online edition, part of the Monster Association Arc.