Cirrus is a male IceWing, Ex-Queen Scarlet's spy in the Talons of Peace, and was revealed to be one of the many forms of Chameleon, a RainWing in possession of Darkstalker's Talisman. Chameleon chose to join wearing an IceWing mask when he infiltrated the Talons because of how few IceWings join. Pyrite's insistence of staying with him every moment is most likely part of the enchantment that Chameleon placed on the mask, so as to keep an eye on her or possibly to keep Hailstorm's repressed IceWing instincts kicking in. He first appears in the prologue of The Lost Heir and was possibly briefly seen at a camp in The Brightest Night. Cirrus also appears in Winter Turning and Escaping Peril.
Cirrus has glittering silvery-white scales with pale purple underscales, silver-white wings, cold, snakelike eyes, and a malevolent gaze. He is quite a bit bigger than Winter and fiercely thin with unusually sharp claws even for an IceWing. He also has a voice like icicles dripping.
Cirrus was part of Nautilus' group that found Webs after the SkyWings abducted the dragonets of destiny. He demanded Webs to tell them how the SkyWings found them, and Webs explained the dragonets' plans to escape and how it was played out. Cirrus asks why they had anything to do with the SkyWings, and Webs simply said that they followed Tsunami and Clay back to the opening of the cave. Cirrus is enraged because he knows they wouldn't be able to survive Ex-Queen Scarlet's arena. When Webs suggested that the Talons attack the SkyWings, Cirrus hints that there are only about forty members of the Talons of Peace. Nautilus mentions his backup plan and says that Webs would be a problem, in which Cirrus pins him down, stating that Webs failed them. He was instructed to kill Webs because of the SeaWing's lack of knowledge of the Talons of Peace's backup plan and allowing the dragonets to escape, and he seemed to take morbid pleasure in the idea of killing the confused SeaWing. However, both he and Nautilus were thwarted and knocked out when Crocodile tackled them, which allowed Webs to escape the execution attempt. This hinted that Crocodile wasn't working for the Talons of Peace after all, and had no problem betraying them.
Sunny spotted an IceWing at the Talons of Peace's camp, which was most likely Cirrus since there are no other known IceWings working in the Talons.
Winter, Qibli, Kinkajou, and Moonwatcher went to the Talons of Peace in order to find a SkyWing that could help them locate the mountain Moon saw in Icicle's dream when she was visited by Scarlet. Upon their arrival, they find a dragon named Pyrite, a nervous and twitchy SkyWing who sports an earring, but Cirrus does not want them to take her. Winter pondered about it and thought maybe because she was an 'animus' he wanted to put the magical genetics back into the IceWing bloodline, but forgets the idea when he notes that Cirrus showed no sign of returning to the Ice Kingdom. Winter is confused because being royalty, he should have recognized Cirrus, and vice-versa, but neither did. Winter asked if Cirrus knew his parents, Narwhal and Tundra, Cirrus said he might, but he was lying, as Chameleon said he had never been to the Ice Kingdom.
Later, on the way to Winter and Hailstorm's Diamond Trial, Queen Glacier says to Winter, "We haven't had a Cirrus in many years", and says she will look into the matter, claiming that he may have been on the outside of the kingdom and therefore didn't have a rank.
Cirrus first appears early in the story, along with the other Talons of Peace, when they attack Peril and Turtle. When Peril introduces herself as the daughter of Kestrel, he says, "That can't be right. Kestrel never had any dragonets". He is questioned briefly for his knowledge about Kestrel, whom he couldn't have met since he joined the Talons after Kestrel went into hiding with the dragonets.
He is later revealed as the IceWing form of Peril's father, Chameleon the RainWing, and working for Ex-Queen Scarlet. He never knew she was his daughter before, as he was told by Scarlet that both of Kestrel's dragonets were dead and that Kestrel had gone to join the Talons of Peace, so he was elated when he learned Peril was alive.
Cirrus is shown to take an almost sadistic pleasure in killing others, appearing more than eager to kill Webs, and even explaining that he intended to rip Webs's heart out and "feed it to the fish". He is very obedient and docile towards Nautilus, and willingly follows his orders when he tells him to kill Webs. In Winter Turning, he is shown to be mildly protective of Pyrite, and most likely doesn't want to let her out of his sight for fear of being executed by Queen Scarlet as Chameleon. He is a spy for Queen Scarlet in the Talons of Peace and seems not to care who is suspicious of him. Chameleon stated that he tried to make Cirrus seem cold and calculating.
- A cirrus cloud is a type of cloud, containing bits of ice, or being made entirely out of ice. It forms at a height around 6,500–45,000 feet (5–13 km).
- Winter described him as acting like an aristocrat.