Marowak was shown to be troublesome since it caused some chaos to other Pokémon at the festival. After getting defeated by Kiawe, nonetheless, its problematic side has begun to converge as it has started to respect his skills as a battler, which is one of the reasons it chose him to be its trainer with the other reason being it can learn a lot from him. Still, it doesn't trust Turtonator much owing to the experience of being defeated by Turtonator as well as its bellicose personality and always wants to fight with Turtonator due to seeing it as a rival.
It loves to dance around with its bone, especially when it's thrilled.
Marowak also had a short rivalry with a fellow Marowak from the Kanto region only to be restrained by both Brock and Kiawe. It also had a mischievous side by attacking towards the wild Onix's head using its bone when Brock tries to calm it down.
Marowak, as a wild Pokémon, first appeared in the crowning ceremony and stole the crown that Olivia was going to crown Litten with its bone before causing more havoc and running away. With the help of three hikers, Kiawe managed to find Marowak, who was practising its dance and challenged it to a battle. However, thanks to the crown it had stolen, Marowak was able to dodge Turtonator's attacks as well as Turtonator's Z-Move and defeated Turtonator, which caused Turtonator to have severe injuries. After Turtonator was recovered and had a practice match with Pikachu the day before, Kiawe challenged Marowak, who wounded the hikers' Magmar, to a rematch in which it got defeated this time. Impressed by Kiawe's skills, Marowak asked if it could come with him after it returned the crown. Kiawe accepted its offer and caught it thus adding it to his team, though it still wanted to continue fighting with Turtonator and got stuck at Tutornator's belly-hole until Kiawe helped it to get out. Then it got crowned in the ceremony and was ready for a photo with its new trainer, Turtonator and its trainer's friends with their Pokémon which the hikers' appeared in a few of the photos jumping in somewhere in them.
Marowak and Turtonator were seen arguing and later they began to fight, and Marowak got its head stuck in Turtonator's belly-hole and Kiawe recalled them back into their Poké Balls. It was then seen eating its food with the other Pokémon while glaring at Turtonator.
At Prof. Oak's lab, Marowak met a fellow Kantonian Marowak and the two soon was about to fight. Togedemaru was unable to calm both them down and got chased instead. Pikachu had enough with the chaos and used his electricity to shock everyone, causing Marowak and Popplio to get separated from the group. Then, when Ash, Sophocles, Kiawe and Brock encountered an Onix, Marowak suddenly appeared and threw its bone at the Onix, enraging the wild Onix and the guys had to run. After Marowak and its other friends were saved by Ash's Lycanroc, Brock's Crobat and Misty's Staryu, Jigglypuff made everyone fell asleep, thus it got its face drawn by Jigglypuff.
Marowak watched the battle between Kiawe and Brock at Cerulean City Gym. It was furious to see Kiawe's loss to Brock and his Steelix and it continued to scold him and Turtonator even after it headbutted both of them.
|Flare Blitz +||A Crowning Moment of Truth!|
|Shadow Bone||A Crowning Moment of Truth!|
|Iron Head +||A Crowning Moment of Truth!|
|Headbutt*||A Crowning Moment of Truth!|
|+ indicates this Pokémon used this move recently.*|
- indicates this Pokémon normally can't use this move.