Kubo encountered Beetle when he and Monkey were guided by little Hanzo to his lair. Beetle claimed that he was a samurai and Hanzo's apprentice, or so it was due to his expertise with arrows and weapons. Monkey reluctantly allowed him to join the quest due to their clashing personality, but their relationships improves as the time goes.
By the climax of the film, it's revealed that he was in fact, Hanzo's cursed form, and in the ensuing battle, he and Monkey was killed by Washi, the very fight which also took Washi's own life as Kubo killed her with a blast of magic before giving the final blow on Monkey. Despite his death, however, Beetle's influence, alongside that of Monkey's, was the catalyst that ensured Kubo's victory against his enemy The Moon King.
He was voiced by Matthew McConaughey, who also played Buster Moon.
Although the movie never showed Beetle during his samurai years, Satiaru kept remembering him for his kind demeanor, sense of humor and charisma. According to her, Hanzo was a warm and noble person, very caring and attentive for the well-being of others. He was also something of a romantic do to the fact that he fell in love with the goddess Satiaru while the latter was trying to kill him at their first encounter. His sincere love had moved her, and as such, Hanzo also demonstrated a strong sense of empathy. As a father and husband, Hanzo held his only son and wife very close to him, so much so that he had apparently commissioned a family portrait, placed at the entrance into his study. The love for his family is made clear at the movie's end, when he is finally reunited with Satiaru and Kubo.
While under the guise of Beetle, Hanzo kept trying to piece together his forgotten life, to that end he became a hoarder of samurai paraphernalia. During this time, although he had become certain of his heritage into the Beetle Clan, he had all but forgot that he was Hanzo and instead came to believe that he had been one of Hanzo's subordinates. Because of this he displayed a great sense of pride and admiration for his past identity. This respect rubbed-off on Kubo shortly after their introduction to one another, with Beetle vowing to defend the young man do to their connection as clansmen. Ironically, this respect slowly turned into a father-son type relationship, with Beetle praising the boy for his great inner strength and courage.
Also ironic was his relationship with Monkey. At first, Beetle's silly quirks and attitude, namely his sense of humor and lack of a common sense. She saw him as being a bad influence on Kubo, but soon came to realize that he only wanted to defend and nurture the boy just as much as she wanted, most notably when Beetle praised Kubo for taking care of his own mother and when Beetle swore to defend Kubo after Monkey had passed away. Their relationship, in time, had returned to its former romantic status. While on the beach of the Long Lake the two of them argued over Kubo's safety, much like a married couple, but while on the ship they began flirting. After hearing Monkey express her fear over her inevitable death, Beetle consoled her with the though that Kubo would never let the memory of her fade away. This relationship ultimately returned to its original form after Beetle identity as Hanzo had been revealed, with Beetle reminding the dying Monkey of his eternal love for her.
Beetle was once named Hanzo, a legendary samurai who lived in the beetle palace and fought alongside his army. He and his men were known to have survived a harsh blizzard and still marched on, adding to his legendary reputation. He was also, as expected, a great warrior in the fields of both swordsmanship and archery.
At one point in his life, Hanzo had started a quest to find the Sword of Unbreakable, Breastplate Impenetrable, and Helmet Invulnerable due to him questioning the Moon King's ways to managing his reign. Because of it, the Moon King sent his three daughters, the elder Satiaru, and the twins Karasu and Washi, to kill Hanzo for his crimes. Satiaru arrived before her twin sisters and challenged Hanzo to a fight, to which Hanzo answered. The two had a long fight when suddenly Hanzo, whom unexpectedly developed a crush on his opponent, said, "You are my quest". This caused Satiaru's cold and dark heart melt, resulting their fights abrupt end in a draw. Their love for each other was so strong that Satiaru decided to abandon her place in heaven and marry Hanzo, the ultimate result of which was their child, the boy named Kubo.
Unfortunately, the Moon King, along with Satiaru's sisters felt betrayed by her actions and as such stormed the Beetle Palace, presumably murdering the entire beetle samurai clan. The Moon King took away one of Kubo's eyes, but Hanzo and his army fought the Moon King and the sisters, allowing Satiaru and baby Kubo to escape. All of the samurai were vanquished except for Hanzo, who was cursed with memory loss and took the form of a beetle-like man.
Meeting Kubo and Monkey
Eleven years after his defeat, Hanzo, now going by the name Beetle, became a recluse living in a cave beneath a giant statue somewhere in the middle of barren snowy wasteland. He spent most of his time collecting artifacts that reminded him of his noble past: armor, swords, a war banner with his clan's crest, and various other assorted gear. One day, while travelling along the wasteland Beetle spots Kubo, Monkey and an origami Hanzo walking through the snow. As the three make their way to the warrior statue Kubo and the origami Hanzo are grabbed by Beetle and brought down to his lair. At first, Monkey believed this to be an abduction and chased after Beetle and ready to kill him, but she is interrupted by Kubo who immediately realized that Bettle merely had a fixation for the origami Hanzo. Beetle explains to them his fragmented history, how he believes himself to have once been a samurai serving under Hanzo, his supposed master, and that he had been cursed with memory loss. Although Monkey is reasonably skeptical do to Beetle's amnesia, Kubo warms up to him. The boy reveals that Hanzo was his father, despite Monkey's protests. Beetle is overjoyed to hear this news and joyfully picks the boy up, vows to protect his young master and even offers to assist the two wanderers on their quest to find Hamzo's magic armor. Monkey questions Beetle's usefulness to which the cursed man picks up his bow and arrow set and demonstrates his remarkable archery skills, namely by shooting four arrows consecutively in the same spot a la Robin Hood. With his talents having been tested Monkey begrudgingly accepts Beetle on her and Kubo's quest, although she continues distrusting him.
Skirmish against Gashadokuro
The newly formed trio journey through underground tunnels until they come across a cave entrance shaped in the form of a skull. As they inspect the entrance Beetle accidentally breaks one of the "teeth", which triggers a mechanism that causes the cave ceiling and floor to collapse, so the trio plummet further under the earth. They safely land inside a chamber wherein a katana is jabbed inside a massive, golden skeletal hand, so Monkey assumes this to be The Sword Unbreakable. Beelte volunteers to remove the sword, but in doing so awakens the chamber's guardian, a Gashadokuro, a giant skeleton warrior. Monkey uses the sword to strike at the monster, but as it turns out it was merely a regular katana, and the real Sword Unbreakable is lodged into the skeleton's cranium, among several other swords.
A fight ensues, wherein the Gashadokuro grabs Monkey while Beetle and Kubo shoot arrows and origami projectiles at the monster's face, respectively. Just as the the skeleton is about to stomp them, Beetle releases his wings, something he had never known he could do, and flies himself and Kubo on top the skeleton's head. While on it's head, Kubo and Beetle begin removing swords and bashing them against the cranium in order to determine which of them is the Sword Unbreakable. But the two of them are soon interrupted as the skeleton grabs Beetle and tosses Kubo off by swinging its skull. Beetle successfully saves Kubo from the fall by pinning his kimono to the wall with an arrow. But, Kubo's kimono tears do to the arrow and as such the boy falls back on the monster's head. Just as Monkey and Beetle are about to be devoured by the Gashadokuro, Kubo pulls out one last katana which luckily proves to be the Sword Unbreakable. With the sword now revealed the Gashadokuro falls apart. Before the trio could hit the ground Beetle grabs Monkey and Kubo and flies them out of the chamber through an entrance, again shaped just like a skull, and abruptly crash into a sandy beach next to The Long Lake, a colossal lake.
Searching for the Breastplate Impenetrable
While on the beach Monkey refuses to swim across and prefers walking around the lake, but Beetle would much rather swim. She and Beetle begin an argument because of this, with Monkey clamming authority over the quest as well as Kubo's well-being. Meanwhile, Kubo begins playing his shamisen and realizes that his magic can also manipulate leaves and wood. He then uses this power to construct a caravel out of leaves and and a log, thus allowing the trio to sail across the lake. Both Beetle and Monkey are left stunned by the boy's feet. While sailing, Beetle, Kubo and Moneky begin bonding much like a family, with Beetle teaching Kubo how to fish using archery, Beetle and Monkey flirt with each other and later, during dinner, Kubo shares with them his stories loving with his mother and how he struggled to make life better for her. Beetle commends the boy for his kindness. But just at that moment a massive storm cloud is headed their way, the sun begins to set and the origami Hanzo points towards the next piece of the armor, The Breastplate Impenetrable, seemingly located under the lake. Beetle, yet again, volunteers to go after the second piece of the armor, but is warned by Kubo about the danger beneath the lake. He tells Beetle about the garden of eyes that traps you into a trance should you stare into the eyes and thus keep you under the lake forever. Nevertheless, Beetle jumps in after the breastplate.
Nighttime falls and Beetle hasn't returned yet, which prompts Kubo to jump in after him. Monkey is just about to go after him but is caught into a fight with Karasu, one of the Moon King's twin daughters. During the fight Beetle surfaces, having forgotten to bring back the breastplate and instead brought back an arrow with a fish that had been lost while fishing. He is then informed that Kubo went after him, so Beetle goes back down after the boy. Back underwater, Beetle notices that Kubo has found the Breastplate Impenetrable, but has succumbed to the garden of eyes' trance and is about to be eaten by the huge maw at the bottom of the lake. Beetle rescues Kubo by shooting arrows into the eyes and brings him back to the surface. While they were gone, Monkey had killed Karasu, but the ship was left greatly damaged. Fortunately, Kubo survived drowning and unconsciously restored the ship. Also, while he was under the eye's influence Kubo discovered that Monkey was, in fact, his mother, her soul now tethered through the monkey charm he carried all of his life.
The Story of how Hanzo met Satiaru
Having landed their ship to shore, the trio make camp in a nearby cave. Both Kubo and Beetle have become fascinated with Satiaru having become a monkey and wish for her to reveal her past to them. Monkey gives in and tells them her story, with Kubo providing music for the occasion. She reveals her battle against Hanzo over the sword, breastplate and helmet, and how she fell in love with Hanzo after gazing into his eyes and realizing the warmth and care inherent in human nature, how they eventually gave birth to Kubo and later, how the Moon King destroyed their lives together. She reveals to that the Moon King wants to gauge out Kubo's eyes so he can become divine as he is, but in the process would also leave Kubo emotionally distant from humanity.
After tucking Kubo to bed Monkey groans over a wound she got during her fight with Karasu. Beetle notices anhd tries to help, but Monkey declines. Beetles questions why Monkey did not reveal her true identity sooner, to which she says that the magic which kept her alive was wearing off and fears that Kubo will be left alone after she has disappeared. Beetle comforts her, he vows to protect Kubo after she has gone. He also tells her that despite her departure she would continue to live on so long as Kubo continues telling her story to the people around him. Monkey is left very grateful for his encouragement.
Battle in Hanzo's Fortress and Demise
The very next morning Kubo wakes Beetle and Monkey up in order to travel to the location of the Helmet Indestructible, which he had heard night before during a dream where an elderly blind man revealed it to be the beetle clan's derelict fortress. Following his hunch the trio make their way to the abandoned samurai fortress, reaching it the following night. As the trio make their way into Hanzo's old study where the location of each armor piece was written down the helmet in nowhere to be found. Beetle questions the reason as to why the helmet would even be in the fortress while Monkey discovers the helmet's true whereabouts in a document found on a desk. Just as they make their way into the inner courtyard, the trio is ambushed by Washi, the last twin, who uses supernatural smoke to restrain them. Angered by Beetle she finally identifies him as Hanzo, whom she and the rest of her family had cursed for "stealing Satiaru's soul". Beetle is then tossed against a wall and Washi continues her mission, approaching Kubo. But the boy breaks free and breaks the lower half of her mask and destroys the pipe which emanated the mystical smoke. Monkey has a brief scuffle with her sister, but her earlier wound prevents Monkey from winning. She is saved by Beetle who tosses a katana into Washi. He then runs off to console the severely weakened Monkey, to whom he says the following words "You are my quest. You always have been!" Unfortunately, their family reunion is cut short as Washi fatally stabs Hanzo in the back with the katana he had stabbed her with. His death was instant, with no chance to leave any last words. She then proceeds to murder Monkey, but in the process she herself is destroyed by Kubo's magic. The following morning Kubo grieves for his parents' loss. Nontheless continues questing for the Helmet Invulnerable, which was located back at the village where he had lived his entire life. Before leaving he wraps his father's bow string around his left arm, alongside the strand of his mother's hair he gained before his journey had started.
Reunion in the afterlife
Although dead, Hanzo and Satiaru indirectly help Kubo defeat the Moon King. At the climax of his battle with his grandfather, Kubo uses a strand of his mother's hair, a strand of his own hair and his father's bow string to replace the shamisen strings that had been broken and with the instrument's magic Kubo summons the memories of the departed and overpowers the Moon King. With the Moon King finally defeated and brought down to earth Kubo lays his parents to rest at the village Obon Festival. And as he places their lanterns into to river so their souls may pass over Kubo is visited by Satiaru and Hanzo, now restored to their human appearances.
Powers and Abilities
Swordsmanship - Although never actually demonstrated during the movie, Hanzo was revered for his amazing grasp of kenjutsu. As a comparison, he could match skill with Satiaru, who was an accomplished swordsman herself.
Archery - Throughout the film Hanzo, under the guise of Beetle, showed remarkable precision with a bow. He could shoot four arrows consecutively in the same spot and was able to pin Kubo against a wall with an arrow while the boy was falling and perfectly avoided injuring him.
Heightened coordination and strength -