Captain Sirryu is the leader of the Spicivores, generally not seen to many individuals, though he has had frequent talks with Grandis in the past. Apparently, Grandis has the ability to control Sirryu's mind and remotely control the Spicivore Empire on his own accord. Originating from Grandis's formerly fictional Spore save file, they inherit their main traits from the save (All Blue Card Bonuses), and are known to be highly bipolar in nature. Sirryu, on the other hand, is noted as being a very tough nut to crack in regards to how serious of an individual he is.
Captain Sirryu, although being involved in several other scenarios, was not a major character in any story until here. After seemingly rescuing his species from going feral, he had one goal in mind; using all of the remaining population as suicide bombers to attack the newly arrived Dogma, an Omnideity who awoke to destroy all of Ultimoria and it's ilk across all of history. Captain Sirryu, not wanting any of it, simply sent his best weapons and suicide bombing squads at Dogma, and even forced women and children to take part in the attack out of sheer desperation when it looked like Dogma was not being damaged by the attacks he was sending; he was outright stalling his attack against Ultimoria, or, more specific, Captain Sirryu.
Apparently whatever Sirryu did that made his species so feral to begin with was so revolting in Dogma's mind that he was sparred until he was the very last Ultimorian of any significance left alive, just so he could have a front row seat as every other Ultimorian Deity got destroyed by Dogma. In a futile attempt to beg for mercy, Dogma's response was that he would never accept a deal with a demon such as him, and promptly crushed Sirryu like an ant, which in turn destroyed his entire species along with him.