Boulder

Boulder is a skinny silver tabby tom with a ragged ear and blue eyes.

Into the Wild

 * He was a friend and rogue follower of Brokenstar, and was one of the warriors in his circle of "elite warriors". When Firepaw, Yellowfang, Whitestorm, and the ShadowClan elders and ThunderClan patrol came to rescue the kits, Firepaw defeated him, sending him running into exile.

A Dangerous Path

 * When Tigerstar became leader, Boulder was brought back into ShadowClan with the other rogues. He was welcomed among them.

The Darkest Hour

 * In the prologue, he and Tigerstar went into BloodClan territory so Tigerstar could meet Scourge. When Scourge killed Tigerstar, Jaggedtooth joined BloodClan, and Boulder thought it was worth betraying BloodClan so he could get his claws in Jaggedtooth's fur. He fought alongside LionClan (the four Clans combined, led by Firestar) to fight BloodClan.

Into the Woods

 * He was introduced by Tigerstar as one of his "best fighters". He was also seen plotting with Tigerstar some other warriors near the end of the book.

Midnight

 * Boulder does not formally appear in Midnight, but is listed in the allegiances.

Dawn

 * He was now an elder of ShadowClan. When the Clans are deciding where to go, Blackstar says ShadowClan is going to BloodClan's former home, and that one of their elders, Boulder, used to be a member of BloodClan and can show the way.

The Sight

 * Leafpool gets news from Littlecloud that Shadowclan has lost an elder due to Greencough, which could have been Boulder, as he doesn't appear in later books.

Secrets of the Clans

 * Boulder gives the tour of the ShadowClan forest camp.