Gatsuki grew up with an average childhood part of a strict and popular clan in the Land of Rivers. He had two mothers and a father, as well a seven siblings. He was the second eldest of his siblings. He joined the academy at an average age, no real prodigy. By this time, he had gained the power to summon an insect, part of his clan's special talents. He took the lunar moth as his summoning and seemed to enjoy using it. He led a relatively normal life until Kuromura Kotaro came into the Land of Rivers, conquering many villages, including Gatsuki's.
However, Gatsuki showed no hatred for Kotaro's murdering of his family. In fact, Gatsuki was smiling the entire time. He became intrigued by Kotaro's power and requested to join his army. With his powerful summonings, Gatsuki was granted entrance to the army. Gatsuki proved to be a loyal subordinate, although, he does have the tendency to back away from certain requests.
During the Shippuden, Gatsuki seems to battle Uchiha Sasuke twice, the second time with Tsukuyomi Ruriko present. Unfortunately, the second time is what revealed Gatsuki's extreme surprise and pain. As he anticipants Sasuke's moves, Ruriko goes in and bites Gatsuki's wrists, ultimately tearing off his hand. At that moment, Sasuke kills Gatsuki's summoning, Hakai, a giant bloodythirsty lunar moth. Gatsuki then retreats as quickly as possible.
Gatsuki is a rather calm shinobi. He does smile a lot and his attempts at a cold fascade don't work. Gatsuki is pretty mature, which is why he hates teenagers. One of his biggest peeves is anyone between the ages of 12 and 20 because he claims they are overconfident and arrogant. It doesn't help that he travels with Kaede, who is within that age range. Gatsuki is constantly scolding and badgering her for acting immature. However, Kage is just half a year over Kaede's age, which apparently matters to Gatsuki, so he respects him just a little more than he does Kaede. The most emotions that are ever 'seen' on Gatsuki are embarrassment, surprise, and relaxation. Gatsuki doesn't have a temper, so it's hard to tell when he's mad.
As for Kotaro, Gatsuki shows excellent loyalty to him. Gatsuki rarely resists anything Kotaro says, unless it has to do with torture or something that involves too much work. It's not that Gatsuki is lazy, but he just disagrees with what deserves more attention. If Gatsuki doesn't want to do something Kotaro says, he will easily convince one of the other subordinates to obey him. It's kind of a Tom Sawyer situation, excluding the laziness.
As for romantics, Gatsuki doesn't seem to show much public interest in it. He will compliment beautiful women (And nature, especially), but he never means it to be flirtatious. However, in private, Gatsuki does like reading romantic poems as well as writing them.
Gatsuki has snow white hair, the tips a pale green. His hair is styled just under his ears and pretty straight, but choppy. His eyes are a pale green, almost teal, but not quite. He wears a green bandana sort of clothe over his nose and mouth that ties at the back of his neck. The bottom of it connects to a high-collar white shirt with long sleeves that are bandaged to his wrists. The bandages also wrap around his hands, but not the tips of his fingers. He also has flaps connecting his sleeves to his torso. He wears a pair of teal pants that mostly cover his dark green boots with bandages around the toes of them. He wears no headband.
Gatsuki comes from a clan where summoning insects is their talent. However, it's nothing like the Aburame Clan's technique. Gatsuki loves summoning moths, particularly lunar moths. Two of the largest that he has are brother and sister, Hakai and Kirei. However, it's revealed that Hakai dies after being hit with Sasuke's chidori, much to Gatsuki's disappointment. Hakai was Gatsuki's only large offensive summoning because his sister, Kirei, is a defensive moth as well as a distraction with the beautiful designs on her wings.
Gatsuki is also seen summoning a swarm of little dark moths, which he calls vampire moths. They attack as groups and tear bits of skin off their victim. They are very hard to control, but Gatsuki manages just fine. He can also use a bit of earth ninjutsu, but he rarely uses it. If he does, it's mostly to trap or defend.
Gatsuki has no taijutsu at all. In fact, he's very much a long range attack. He can't block very well nor attack, seen when he's easily punched in the jaw by Ruriko.
- Gatsuki's name means lunar moth, ironically, while his last name means summons insects.
- Gatsuki's oldest brother, Tonbo, survived the attack, but fled as soon as possible. His whereabouts are unknown, but this doesn't seem to concern Gatsuki very much.
- Gatsuki's favorite food is unadon while his least favorite is sushi.
- His hobbies are bathing, watching animals/bugs/humans, and writing poems.
- Gatsuki's favorite word is "nature".