Darkstripe was a warrior of ThunderClan and a former apprentice of Tigerclaw, one of the senior warriors. He was Tigerclaw's closest friend and biggest supporter, and as such had a highly negative opinion of Fireheart, Tigerclaw's chief rival. Darkstripe refused to trust Fireheart due to his kittypet origins and openly mocked any cat who thought otherwise. He was also selfish, secretly taking actions that benefited himself and not the Clan whenever possible.
When Tigerclaw was exiled from ThunderClan in Forest of Secrets for trying to seize power from Bluestar, Darkstripe voiced his disappointment that Tigerclaw did not tell him he was potting with Brokenstar (it is interesting to note that he did not appear to have a problem with Tigerclaw's plan itself, but rather that he was not allowed to be a part of it). Darkstripe's lonely path of a devoted follower increasingly reduced his popularity in the Clan, and in A Dangerous Path, he began secretly plotting with Tigerstar, now leader of ShadowClan, across the border in order to bring a pack of dogs upon the camp and save only Tigerstar's children, Bramblepaw and Tawnypaw, from the ensuing chaos, but not Tigerstar's mate, Goldenflower.
After this failed, during The Darkest Hour, he attempted to murder his half-sister, Sorrelkit (later Sorreltail), with deathberries when she discovered his meetings with Blackfoot, Tigerstar's deputy, and he was exiled from the Clan as a result. Darkstripe immediately ran to Tigerstar's side and helped kill one of Bluestar's children, Stonefur, but when Tigerstar was later murdered by Scourge, Darkstripe was left completely alone. His resulting madness culminated in the battle with BloodClan; he abandoned all loyalty to his Clan and tried to murder Firestar in "revenge" for Tigerstar's death. He was stopped and killed by his half-brother, Greystripe, during the battle.
Because of his cruel and selfish actions, Darkstripe's spirit, along with Tigerstar's, was denied entry to StarClan and instead sent to the Dark Forest, much to Darkstripe’s confusion and dismay, showing that, even in death, he saw nothing wrong about what he had done.
Personality and Traits
Darkstripe is an extremely arrogant and self-centered individual. He is shown to be very rude and disrespectful, criticizing even the littlest mistakes made by others, openly mocking any cat who disagrees with him, and refusing to listen to any criticisim directed at him. Although he claims to be loyal to ThunderClan, he is actually very selfish, secretly taking actions that benefit himself, instead of the Clan, whenever possible. This was shown when his companion, Longtail, caught a plump squirrel, and Darkstripe encouraged themselves to eat it since prey was scarce at the time. After eating it and returning to camp with a smaller catch, Poppydawn, who needed food, died of illness. While Longtail felt guilty about this, Darkstripe did not; he saw nothing wrong about what they did, and coldly ordered Longtail not to tell anyone, threatening to lie that it was all his fault if he did. In the end, Darkstripe would ultimately betray his Clan entirely for the sake of his own ambitions.
Darkstripe is the biggest supporter of Tigerstar, whom he regarded as the greatest cat ever. However, when it was revealed that Tigerstar had tried to murder Bluestar in order to become leader, Darkstripe refused to follow him into exile, not because he was loyal to ThunderClan, but rather because he was disappointed that Tigerstar didn't tell him about his plans. Despite this, he continued to distrust Fireheart, the cat who exposed Tigerstar's treachery, and insulted him at every oppotunity.
When Tigerstar became leader of ShadowClan, Darkstripe immediately rekindled his alligiance to him and began plotting with him to destroy ThunderClan. He even tried to poison Sorrelkit, a defenceless kitten and his own half-sister, to keep her quiet about his meeting with the ShadowClan deputy, Blackfoot.
Darkstripe is shown to be incredibly deluded, believing himself and Tigerstar to be the strong and worthy ones, and Firestar to be the weak one, despite there being strong evidence to the contrary. He does not consider himself or his actions to be wrong in any way, and thus was both shocked and confused when his spirit was sent to the Dark Forest instead of StarClan after his death. Like Tigerstar, he is also hypocritical, as he often criticizes those who break the warrior code, but is perfectly willing to break it himself if it suits his own personal needs.