Captain Whisker is a robot pirate, who serves as the main antagonist of Sonic Rush Adventure. He has two parrot-like sidekicks named Mini and Mum.
Whisker steals the Jeweled Scepter, despite Blaze's attempts to stop him. Sonic and Blaze worked together to try to defeat Whisker. Whisker sent his robots, all of which had "Ghost" in their name after Sonic and Blaze. Although they always defeated his robots, Whisker always escaped.
Eventually, Sonic and Blaze entered Whisker's hideout. There, Johnny was revealed to be his first mate. They mentioned working for a boss, but Sonic and Blaze defeated them, and they ran. Whisker captured Marine the Raccoon and took her to his ship, the Big Swell. Sonic and Blaze fought his robot, Ghost Titan, and after an intense battle, Sonic and Blaze destroyed the giant robot, and the resulting explosion killed Whisker and his crew and sunk his ship.
- Whisker looks somewhat similar to Eggman, foreshadowing that Eggman is his creator.
- Captain Whisker is the only major villain that fans believe actually died in the Sonic series (although there hasn't been much speculation about SCR-HD's survival either). Though all of the following are likely to have died, fans believe that they didn't because:
- Black Doom said he was immortal (Shadow defeats him with Chaos Spears to the eyes, he falls, expressing shock at his defeat due to his power and apparent immortality, and is never seen again)
- Iblis and Mephiles the Dark are speculated to still exist in the "alternate timeline" due to Crisis City being accessed in Sonic Generations (Princess Elise blows out the flame that would separate into the two, erasing them completely, and it could be argued Time Eater can access erased parts of the timeline)
- The Ifrit is speculated to have survived the fight with Shadow and Metal Sonic and just been sealed in his dimension with Eggman Nega (even though he falls and explodes)
- Eggman Nega is never confirmed dead (he was last seen trapped in the Ifrit's dimension and is likely to die without any food or water).
- Dark Gaia is speculated to be alive because Professor Pickle talks of the balance of light and dark and says the darkness may have been put to rest rather than destroyed. (when Sonic smashed through his center eye, blood gushes from him as he slowly decays)
- Metal Sonic remains in the White Space for Sonic to fight him again (though re-entries of the same levels are considered non-canon once Sonic has defeated them, and Metal Sonic explodes when Sonic kicks him, completely destroying him) and returns in Sonic Mania, still active.
- Eggman says he will control the Deadly Six again someday. (After being beaten by Sonic, Zazz, Zomom, Master Zik, and Zeena explode in a puff of smoke while Zor and Zavok fall into lava, and none are seen again afterwards).