Chao gardens sit beside extra multiplayer in Sonic Adventure 2 Battle, the GameCube edition of the hero and dark stories. It was a launch-window title for the console, adding battle modes on top of Shadow's introduction and the Space Colony ARK.
Hero and dark campaigns still split Sonic's friends from Eggman's, and the garden still raises Chao between those stories. The Dreamcast original told the plot first; this edition is the one that padded the versus menu for the new machine.
Launch-window buyers met Shadow here if they had missed the Dreamcast. The extra multiplayer is why the title grew the word Battle.