Jonny Diamond was one of the Aquatics. He was apparently very intelligent, as he designed the Jeweled Star, which netted Max and Nudge out of the sky. He told Max not to be afraid of Rizal, who seemed cruel but was just trying to protect everyone. He seemed to be a very good-natured person, but tells Max that “there’s always someone in the group who’s a little vulnerable.”
He has lots of conspiracy theories about what happened to cause the apocalypse. He’s very well-informed and is actually right on most of them. He wants to make more weapons and prepare the group to fight back.
He goes out swimming with Max and Nudge and gives them both oxygen tanks to carry. While navigating through the low-visibility, ashy water, they’re attacked by eels. Max uses her oxygen tank to fight back, but one of the eels attaches onto Jonny’s chest and burrows into him. The others swarm him and he is quickly killed. His death leaves a big impression on Max, but none of the other Aquatics seem concerned. Rizal casually says that they have deaths every few days, usually the “less advanced” kids.
He was a skinny kid wtih glasses; his poor eyesight is mentioned several times as a vulnerability. Like other Aquatics, he had gills behind his ears and could breathe underwater. He may have scaly skin.