Possibilities

"That guy easily countered all of Sealyn attacks… he was also able to control the water around the bodies of the sea warriors and make them feel bad," Seara said. "I don't know how he did that, but that decreased our strength by half."

Hydrogen sulfide is a colorless, highly toxic gas that can be produced naturally in marine environments through various processes, such as the decay of organic matter in sediments, volcanic activity, or certain bacterial actions. When present in high concentrations, hydrogen sulfide can interfere with the respiratory systems of fish by reducing the oxygen levels in the water. This can lead to fish experiencing respiratory distress or suffocation, making it challenging for them to respire normally.