Seven

Seven doesn't know he has a twin brother with practically identical features: long black hair, black eyes, the same height, and very prominent ears. But his twin had a very different personality; he was cheerful and mischievous, but he was locked up in chains in Xuanwu.

His twin escapes from the Xuanwu and arrives at Chicken Island

His past as a young assassin
Originally, his code name was simply Seven, and he was the strongest assassin in the world.
Early prodigy: At 15, he joined the Shadow Assassins organization in Xuanwu, and at 16, he obtained the legendary Thousand Demonic Piece Sword. Feats: At 17, he killed the king of Stan, and at 19, he defeated a sacred beast to protect a woman known as the Girl in White. (The Betrayal)
Despite his cold demeanor, Seven broke the assassins' code by attempting to save the Girl in White. However, she betrayed him, stabbing him in the back. After the attack, Seven fell into the sea and was presumed dead, resulting in severe amnesia and the complete loss of his memories and original abilities.
His life now was rescued on Chicken Island beach by a blue chicken named Dai Bo.
New identity: Now 21 years old, he lives under the name Seven. He remembers nothing of his deadly past.
Profession: He works as a hairdresser by day (using his scissors as his main weapon) and as a (pretty bad) hitman by night to pay off his medical debts.
Personality: Unlike his younger, ruthless self, the Seven of today is absentminded, kind, and possesses strong empathy, which often hinders him from completing his assassination missions. His closest "family"
Dai Bo: He's a blue chicken with sunglasses who acts as Seven's manager and best friend. He found Seven on the beach, and although it sometimes seems like he's just exploiting him to pay medical bills, he actually cares for him a lot. Xiao Fei: Dai Bo's adopted son, a small hybrid chicken (half pigeon) who can fly and has the curious ability to transform into a "muscular chicken" to save Seven when things get tough.
Her love interest (and rival)
Thirteen: She is an elite assassin from Xuanwu who initially tries to kill Seven. Over time, they develop a complicated romantic relationship; she begins to secretly protect him.