Yu-Gi-Oh! Monster Capsule GB

Seto Kaiba possesses the Millennium Ring and is captured by its power while his mind was shattered after losing to Dark Yugi at "Death-T". Kaiba then invites Yugi Muto and all of Yugi's friends to "Duel Tower". In order to get his friends and grandfather back, Yugi has to defeat Kaiba and his minions, the Dark Masters, in the "Monster World Tournament" using "Monster Capsules" (MC). (Yu-Gi-Oh! wiki)