Herring's brother was one of the SeaWing soldiers that appeared in The Lost Heir. He had normal SeaWing features and colors, except he was only seen covered in wounds and with a hole in his gills. Herring uses the hole in his brother's gills as a symbol to which guard he was talking about by gesturing to his neck. He was seen reporting to Queen Coral, and later Tsunami learned that, although he had been badly injured, the Queen would have kept him there so he could report to her.
Herring's brother appears towards the middle of The Lost Heir when he and another guard visit the council. Tsunami can see that both are terribly wounded from a recent battle, and she tries to encourage her mother, Queen Coral, to get them to some healers. Queen Coral eventually agrees, and the dragons who were helping them fly bring both of them to the healers.
Later, when Tsunami goes back to her friends, she has to get the guards to give her the key to take off Clay's chains. After a little convincing, the guards agree, and Herring tells her that she had saved his brother, and if she wasn't there, Queen Coral would have kept him up there for the entire meeting. When she asks about the other guard, Herring tells her that it was "too late", meaning that they had died of their wounds.
Present: Abalone • Flounder • Herring • Herring's Brother • Kelp • Lagoon • Nautilus • Pearl • Piranha • Riptide • Snapper • Squid • Tempest • Tortoise • Urchin • Webs • Whirlpool