Blackback is a loyal Guardian and will attack any intruder. He does not like it when someone jumps into someone else's fight, as demonstrated when he bodyslammed Jean Bart after the latter tried to break up Roddy's fight with Monkey D. Luffy. Like a stereotypical ape, he loves bananas.
As a member of the Guardians, Blackback is a very powerful warrior even by mink's standards and can use Electro. He possesses very high levels of physical strength, having easily picked up and slammed the massive Jean Bart into the ground with only one hand while still recovering from considerable injuries, a feat which shocked the other members of the Heart Pirates.
When Jack claimed victory over the minks, he tortured the strongest warriors; Blackback was among those who are targeted, which is indicative of his strength.
The battle against the Beast Pirates lasted for five days. On the fifth day of the battle, Jack lost his patience and unleashed Caesar Clown's Koro gas, which left the minks poisoned and drastically weakened. As one of the strongest mink warriors, Blackback was crucified and tortured for information regarding Raizo, though he denied having any knowledge of the ninja and his whereabouts. The following day, Jack left Zou after hearing about Donquixote Doflamingo's defeat and capture, and the minks were later saved when Sanji and his group came to Zou.
When Sanji was taken away from Zou by Capone Bege after giving his crewmates the opportunity to escape, Blackback released the chains restraining Brook.
When Monkey D. Luffy entered the Whale Forest, Roddy and Blackback attacked him despite Bepo's assurance that he was a friend. As Luffy clashed with Roddy, Blackback wondered why Roddy's Electro did not work on Luffy before slamming Jean Bart into the ground when the latter attempted to break up the fight. After Wanda arrived and pacified him with bananas, which he happily ate, Blackback retreated on Pedro's command.
That night, when the Straw Hat Pirates arrived at the Whale Forest to see Nekomamushi after visiting Inuarashi, Blackback and Roddy apologized to Luffy for attacking him. Later, upon hearing Trafalgar Law expressing his concern that Zou and its inhabitants would not be safe if the pirates remained on the island, Blackback was touched by his words and shortly afterward took part in a party which lasted throughout the night.
The following day, as Bariete rang the bell and spoke of the arrival of samurai, Blackback and the rest of the minks rushed to Kurau City. When Kin'emon and Kanjuro revealed themselves, Blackback and the minks welcomed them and revealed that Raizo was on Zou before standing proudly at having kept his presence a secret.
When Inuarashi, Nekomamushi, the samurai, and the pirates returned from the Whale Tree with Raizo, Zou began shaking as Zunesha started crying out, throwing Blackback and the others into a state of panic. Jack had returned and was attempting to destroy Zou by killing Zunesha, who retaliated on Kozuki Momonosuke's command and sank Jack's fleet with one blow, calming down Blackback and the others in the process.
Later on, he requested to go with the Sanji Retrieval Team because he had fought with Luffy, but was told to stay behind on Zou by Nekomamushi.
The Guardians accompanied Nekomamushi on his quest to search for Marco. They later arrived at the island where Marco was working as a doctor. The Guardians were asked to wait at the coast while Nekomamushi spoke to him.
↑One Piece Manga and Anime — Vol. 80Chapter 805 (p. 9-11, 13) and Episode 754,
Confronting Luffy alongside Roddy, Blackback attacks Jean Bart for trying to interfere, but is pacified by Carrot and retreats on Pedro's command.