After watching Ash train Rockruff, Kukui noticed the bond they had developed and encouraged Ash to catch Rockruff.
Upon further investigation, they found out that it had been training on Clawmark Hill. Rockruff soon returned injured, prompting Kukui to heal it with a Potion. In Rocking Clawmark Hill!, he and Ash returned home one night, only to notice the absence of Rockruff. At the end of the next episode, he handed Ash a new Pokédex, which then got inhabited by a Rotom. Following Ash's decision to attend the Pokémon School, he allowed Ash to live with him during his stay in Alola. After Team Skull's defeat, he told Ash about Z-Moves and the island challenge. He later watched as Ash battled Team Skull and was impressed by his battling skills. He was first seen entering his classroom, where he was introduced to Ash, apparently not recognizing him from his youth. Professor Kukui debuted in Alola to New Adventure!. While Guzma abandoned his training and established Team Skull, Kukui continued to study under Hala. However, the two had a falling-out after Guzma expressed beliefs that Z-Rings and Z-Moves were pointless. In League Offenders and Defenders!, Hala revealed that Kukui and Guzma were once his apprentices. Soon, Ash was transported back to the present by Celebi, leaving both young boys unaware of each other's real names. He then proceeded to tell Kukui about his Gym and Pokémon League battles in other regions, inspiring Kukui's own ambitions. Ash easily won the battle and taught the young Kukui, whom he started calling "Roarie" (Japanese: ガオ Gao) due to his Incineroar cap, that there was no shame in losing. Due to Ash's mastery of Z-Moves, he started calling him the "Move Kahuna" (Japanese: ワザキング Move King) and asked to battle with him. In addition, he is a childhood friend of Molayne and DJ Leo.Īt the age of five, he met Ash, whom a Celebi had accidentally sent into the past.
He also befriended a Totem Trevenant living in the forests and received a Firium Z after helping to relieve it of its sneezing. The pair would often spend time in the forests of Melemele Island playing with all of the wild Pokémon. At some point, he befriended and later obtained a Litten, which originally belonged to his parents. He would follow the matches along with his Move Index guidebook. Since his childhood, Kukui had been a fan of Pokémon moves, often observing Hala's battles to witness these attacks in action.