Allied Clans


 * Sometimes, in the Warriors series, two or more Clans form an alliance (to some extent).


 * Amongst the Clan cats, alliances of the formal sort are rare; while from time to time, informal alliances that don't result in a name change, happen. Only in very extreme situations, do formal alliances that result in temporary Clan name changes happen.

Fire and Ice

 * ShadowClan and RiverClan form an alliance against WindClan, when WindClan returns to their old territory, since they had been driven out by ShadowClan's former leader, Brokenstar. Both ShadowClan and RiverClan try to chase WindClan out again, but ThunderClan joins forces with WindClan, and together, they defeat ShadowClan and RiverClan.

Forest of Secrets

 * ShadowClan and WindClan form an alliance against ThunderClan, after they learn that Thunderclan is sheltering Brokentail. The two Clans decide to try to kill him themselves, since he had done serious harm to both Clans. ThunderClan is forced to fight back alone, but they drive out the attacking Clans, bravely.

Tigerclan

 * ShadowClan and RiverClan form an alliance, and make a Clan, called TigerClan. Tigerstar, the leader of the newly formed Clan, offers Firestar, Thunderclan's leader, and Tallstar, WindClan's leader, a chance to join TigerClan, but both refuse.


 * Later, TigerClan attacks the WindClan camp, shortly after Tallstar's refusal to join, slaughtering Onewhisker's apprentice, Gorsepaw, and weakening all the WindClan warriors, so to teach them a lesson.
 * Also, Firestar and Graystripe travel to TigerClan, along with their close friend, Ravenpaw, to see that they are keeping half-clan cats prisoners. The trio rescues the prisoners, who are Stormpaw, Featherpaw, and Mistyfoot, but are unable to save Mistyfoot's brother, Stonefur, who is killed by Blackfoot. After Tigerstar dies from being slaughtered by Scourge, Leopardstar is left to lead TigerClan alone. When she is asked to join the newly formed LionClan, she replies saying she will have to think about it or she'll just lead her Clan away. She leads TigerClan to the battle against BloodClan, handing it over to Firestar making TigerClan apart of LionClan.

LionClan

 * Before BloodClan comes to the forest, LionClan was only made up of ThunderClan and WindClan and was lead by Firestar. But later, after BloodClan comes to the forest, ShadowClan and RiverClan join, or at the time, TigerClan. Ravenpaw and Barley join LionClan as well, but only temporarily.


 * Later, LionClan fights against BloodClan, despite who greatly they're outnumbered. Whitestorm, ThunderClan's deputy, is killed during the battle, along with BloodClan's leader, Scourge, who was killed by Firestar. As soon as Bloodclan learns their leader is dead, they retreat, giving victory to LionClan.

Starlight
Mudclaw, Hawkfrost, and other warriors from WindClan, ShadowClan and RiverClan, form an alliance against Onewhisker, believing he isn't the rightful leader of WindClan. ThunderClan joins the battle on WindClan's side to fight off Mudclaw and his followers. Some of the fleeing cats take the battle to ThunderClan camp, while Mudclaw and Hawkfrost take it towards the lake. When Mudclaw tries to kill Brambleclaw, Hawkfrost goes against him, rescuing his brother. StarClan sends lightning to strike a tree, and kills Mudclaw showing that StarClan approves Onewhisker as the rightful leader. Meanwhile at the ThunderClan camp, two ShadowClan warriors fall over the edge into the hollow, bowling Leafpool over, dangling for her life. She is rescued by Crowfeather, and he confesses his love for her.

Twilight
Just near the end of the book, WindClan comes to help ThunderClan fight off the badgers after Midnight takes the warning to them.

Eclipse
In the huge battle before the sun disappeared, RiverClan allied up with WindClan and fought Thunderclan, who allied up with Shadowclan.