When Mohn was a young man, he used Zoroark to battle Hala's Hariyama. Hala was impressed with Mohn's brilliant tactics in that battle. Zoroark was present with Mohn when he and Lusamine comforted their crying baby, Lillie.
Zoroark took the disguise of a Dewgong, watching Gladion and Umbreon fight a Vullaby. It changed its form into a Buneary and snuck away, temporarily gaining Umbreon's attention. When Gladion and Umbreon rested in their camp, Zoroark, as a Fomantis, approached them. Gladion mistook it to be their enemy, and had Umbreon fire Dark Pulse at it. Fomantis defended itself, but lifted off its disguise, showing itself as a Zoroark. Gladion was relieved that he finally found Zoroark, who showed him a vision from the past, where Gladion and his family were united. Gladion was happy that Zoroark has returned, and hugged it. Explaining his quest is to find Mohn, Gladion invited Zoroark into his team, who accepted.
At evening, Gladion and his Pokémon observed the sunset, the night before the Pokémon League finals began.
During the Pokémon League finals, when his Silvally was defeated, Gladion sent Lycanroc. Much to others' surprise, Lycanroc used Night Daze to hit Pikachu, then used Shadow Claw to stop his Electroweb. However, Pikachu snuck behind him and electrocuted Lycanroc with Thunderbolt. Lycanroc started to glow with a strange light, as it unveiled itself to be Mohn's Zoroark. Gladion called upon his father's strength, as Zoroark went to continue battling Pikachu. Zoroark used Night Daze to hit Pikachu even more, who used Thunderbolt to counter it. Zoroark went to use Shadow Claw, and collided with Pikachu's Iron Tail. When Pikachu jumped to avoid its Night Daze, Zoroark came close to him and stroke it with Shadow Claw. To finish Pikachu off, Gladion had Zoroark use the Z-Move Never-Ending Nightmare. Pikachu attempted to escape the Z-Move with Quick Attack, but failed. Instead, Ash had Pikachu use Breakneck Blitz Z-Move. The two Z-Moves collided, and Zoroark and Pikachu were defeated from those attacks.
Per Lillie's request, Gladion sent Zoroark out in his father's room, who could be the key to awaken Magearna. Zoroak was soon reminiscing about Mohn's room. Upon seeing Magearna, Zoroark used its powers to display a vision of the past to Lillie and Gladion. It showed how Mohn was trying to awaken Magearna, and showed baby Lillie about it. Lillie started to cry, wishing to see her father again. At the moment, Magearna was awakened. Lillie hugged the awakened Magearna, which pleased Gladion and Zoroark. Before Lillie, Lusamine and Gladion went on their journey to find Mohn, Rotom took picture of the group, including Gladion's Zoroark.