The show iI was thinking of was digimon fusionDigimon Fusion. While i was looking a few days ago i thought it could be digimon but it only showed me adventure
Mikey Kudo receives the Fusion Loader, creates his own team (Fusion Fighters) and recruits some Digimon partners in the Digital World. There, he learns that Lord Bagramon is attempting to conquer the world by collecting 108 Code Crown fragments and wields the Darkness Loader. Mikey collects some fragments from each zones, but Bagramon steals them and recruits AxeKnightmon. Mikey, Angie Hinomoto and Jeremy Tsurugi are sent back to the human world, but Mikey returns to the Digital World, leaving his friends behind.
From the first episode of season 1:
The story begins with a seventh grade teenager named Mikey Kudo dreaming of commanding a Digimon army. The next day Mikey is harassed by his childhood friend named Angie Hinomoto over standing her up to help the basketball team and his rival named Jeremy Tsurgi demanding a kendo rematch. Mikey spots a dying red creature flickering in static. Wanting to save the creature, Mikey hears a mysterious voice. The mysterious voice presents him with a Fusion Loader. The Fusion Loader absorbs the creature to heal him within the item as Mikey grabs it against his friends' pleas. Mikey, Angie, and Jeremy are then sucked into a portal. They find themselves in a strange world surrounded by a hostile platoon of Digimon under MadLeomon. Mikey, Angie, and Jeremy are rescued by Ballistamon, Starmon, and the Pickmonz before the red creature emerges from the Fusion Loader. The red creature introduces himself as Shoutmon while stating his intent to become the Digimon King of the Digital World. After Shoutmon and his companions fight back against MadLeomon’s troops, MadLeomon absorbs his remaining forces to become Armed MadLeomon. Mikey helps his Digimon friends by using his Fusion Loader to DigiFuse Shoutmon and Ballistamon into an incomplete Shoutmon ×3/x4. After injuring Armed MadLeomon prior to reverting to his usual self, Shoutmon uses the DigiFused Starmon and Pickmonz, in the form of the Sun Sword, to defeat MadLeomon while forcing him back to his original form. A portal then appears. MadLeomon and his minions are recalled by their master named Tactimon. Tactimon is seen conversing with the other evil Digimon over the new turn of events. As Mikey and his friends learn that they are trapped in the Digital World, Mikey, Angie, and Jeremy agree to help Shoutmon and his Digimon friends. Mikey, Angie, and Jeremy are watched from afar by two other groups.
