King Toxinbreath is the ruthless, poisonous leader of the Acid Dragons. He led the acid dragons into battle alongside Catylketz and has performed many evil deeds. He caused the Chernobyl disaster and made his own improvements to the atomic bomb, in turn nearly tripling the potential kills. He is widely feared by humans and dragons.
King Toxinbreath is mainly coloured light or dark green but he has a brown underside and his snout is also lighter. He has a very large wingspan and area, along with razor-sharp claws on each hand. As his name implies, his breath weapon is extremely dangerous, measuring around 0.25 pH, meaning it can dissolve nearly anything. It is so toxic that just 1 cm^3 in the air can kill an elephant in seconds.