"I have my own camp now, and my own cats. My future lies with them, not you. [...] You will always be my father. But you have to let us all be the cats we want to be. I can't come and live with you. I must find my own path."
Thunderstar, also known as Thunder, is a ginger tom with amber eyes and white paws.
Thunderstar was the founder and first leader of ThunderClan. He was the only surviving kit of Clear Sky and Storm. After his father disowned him, he was given the name Thunder by Gray Wing who raised him. As he grew up on the moor, Thunder yearned to live with his father in the forest. However, he constantly grew frustrated with his father's inability to listen to him and his aggression towards outsiders, and rejoined Gray Wing on the moor where his leadership skills excelled. Still yearning for the woods, he created a new group in the forest. His group was renamed as ThunderClan and he later received his nine lives as Thunderstar. His mate, Violet Dawn gave birth to his kits, Lightning Stripe, Sleek Fur, Shell Claw, and Feather Ear. Thunderstar was remembered as one of the most courageous and compassionate founding leaders, developing the sympathetic components of the warrior code.
Thunder is born unnamed to Storm, a rogue, and Clear Sky, along with two other unnamed kits. When the Twoleg den that Storm gave birth in collapsed, it kills her and Thunder's two siblings. He is discovered soon after by Gray Wing and Turtle Tail, and is named Thunder, in remembrance of his mother Storm, and also the tragedy that unfolded when the Twoleg den collapsed. Gray Wing attempts to take Thunder to Clear Sky's camp, but Clear Sky rejects his son, not wanting to harm another cat he cared about. Gray Wing decides to become Thunder's adopted father and takes him back to the moor camp. Hawk Swoop offers to be his adopted mother, since she is already nursing Acorn Fur and Lightning Tail. Despite being raised on the moor, Thunder's heart longs for the forest. When Clear Sky arrives at Gray Wing's camp and asks Thunder if he wants to join his real father's camp, Thunder is a bit hesitant at first, but after questioning Clear Sky, he leaves Gray Wing's camp to be with his father.
As Thunder stays with Clear Sky for a while, he learns that he doesn't particularly enjoy being in his father's group. Clear Sky is extremely critical of Thunder and the two cats frequently butt heads when it comes to making decisions. Clear Sky makes the decision to banish Frost, because the rogue has a crippling injury, and tells Thunder to leave him at the edge of the forest for the maggots. Thunder refuses and leaves Clear Sky's group, horrified at his father's cruelty, and takes Frost with him to Gray Wing's camp. Angry, Thunder claims that he doesn't have a father anymore.
Back at Gray Wing's camp, Thunder is initially concerned by the cats battle training, realizing they were prepare to go to war with his father. Realizing he has no choice, Thunder participates in the training. When Turtle Tail's kits are missing, Thunder and Lightning Tail try to find them in the Twolegplace believing their father Tom stole them. However, they instead find Turtle Tail's body and discover she was killed by a monster on the Thunderpath. Thunder brings the grave news to Gray Wing who mourns for his mate.
Thunder joins the meeting with the other leaders at Fourtrees which soon unravels into a deadly battle. Thunder is horrified by his father's seemingly enjoyment of killing, and screeches for the fight to stop. Fortunately, the spirit cats of their fallen friends appear and demand the cats to unite or die. Gray Wing steps down as leader of the group and passes the role to Thunder. Gray Wing believes that he was suppressing Thunder's natural leadership abilities and wants his adopted son to shine.
The spirit cats pass on another message - to grow and spread like the Blazing Star. Thunder is confused by this message, though he quickly runs into Star Flower, who claims to understand the meaning. Thunder quickly falls for her, and as they grow close, Star Flower informs him about the herb the message is referring to, which will also cure a deadly sickness that was ravaging the cats. Thunder explains Star Flower's information to the other cats, but they are unable to retrieve the herb because of One Eye, a rogue who has been wrecking havoc to Clear Sky's group. During the final conflict with One Eye, Star Flower betrays their plan to her father, breaking Thunder's heart.
He returns to his father's group in the forest with several other of his cats, hoping that his father might help him lead. However, he is repulsed when Star Flower and Clear Sky develop feelings for each other. When his father continues to ignore his advice, Thunder decides he had enough and creates his own group in the forest. They settle in a sandy ravine and he appoints his oldest friend, Lightning Tail, as his deputy.
After Star Flower gives birth to Clear Sky's kits, Thunder visits them. At first, he is envious of his father's visible adoration for his new kits, but he is ultimately pleased the kits would grow up with loving parents. He and Lightning Tail rescue Slash's prisoners and Thunder is immediately awestruck by Violet. He welcomes her and other loners and rogues into his group. When Slash steals Black Ear, one of Gray Wing's kits, Thunder joins in the rescue efforts. He reunites the kit with his father, and stays by Gray Wing's side as he dies. Gray Wing renames the groups into Clans and Silver Stripe names Thunder's group ThunderClan after its leader.
This section summarizes Thunderstar's significant Novellas appearances. If you're looking for a full list, find one here!
In Thunderstar's Echo, after receiving his nine lives, he is renamed as Thunderstar. He, his deputy Lightning Tail, and their medicine catCloud Spots lead ThunderClan into an era of prosperity. When dogs raid the camp, Thunderstar and Lightning Tail track them down to kill them. Unfortunately, the dogs overwhelm them, resulting in Thunderstar losing one of his lives and Lightning Tail dying. Thunderstar buries his best friend before returning to ThunderClan where Violet Dawn is giving birth. She gives birth to four kits, including Feather Ear, Shell Claw, Sleek Fur and Lightning Stripe, whom he names after his fallen friend Lightning Tail.
He is the only one of the first leaders who was not born with a two part name, or did not change his name to be so.
While originally stated to have not taken -star as a suffix of his name, this is later contradicted by Moth Flight's Vision, and further supported by Secrets of the Clans, both of which address him as Thunderstar.
There has been some contradictions as to how Thunderstar got his name. While originally said to have gotten his name because of the Thunderpath, this is later changed to him having used thunderstorms to his advantage while hunting, using the thunderclaps to confuse his prey. Despite these mentions of how he got his name, The Sun Trail states that he is named after the collapsing building he was born in, and also after his mother, Storm.
He has been mistakenly called golden, and depicted as a solid cat with white-rimmed eyes.