Medalink
Medalink (メダリンク Medarinku), introduced in Medarot 2, allows players to face other Medarotters via the Internet instead of engaging in physical Robattles. This "in-universe", not to be confused with the real battle via link cable.
Medalink typically operates on a ranking system, with the final battles being against top Medarotters. However, if two people are using Medalink simultaneously, they can challenge each other regardless of their rankings. Accessing Medalink usually requires specialized terminals.
Medalink can be seen as an offline simulation of what a linked Robattle between two individuals would be like.
Medarot 2 / Medarot 2 Core
Ikki Tenryou can start using Medalink as soon as he gains access to Medaropolis. The Medalink terminals are located on the second floor of Medashop, with each terminal providing access to a specific segment of the ranking.
Unlike in later games, Ikki cannot climb the entire ranking right away. He must progress through certain points in the story to unlock access to higher ranks.
Medarot R / Medarot R Parts Collection
Ikki again can access the Medalink terminal immediately upon reaching Medaropolis. Additionally, several terminals are available on other maps throughout the game.
Unlike in Medarot 2, Ikki can challenge the entire rank regardless of his progress in the story.
Medarot R Parts Collection revolves around Medalink's ranking system, which mirrors the list in Medarot R but includes a few different Medarots for greater variety in part collection.