Both the new and old Dream Eaters are Spirit types, so Sora and Riku can use them in battle. The Dream Eaters’ link attacks are activated with the touchscreen.
The Koumori Bat’s link attack is Dark Fierce, which temporarily gives Sora and Riku long claws and with them, new combos.
This Dream Eaters’ link attack is Ghost Vacuum, which sucks in enemies and spits them out. Hence the name.
This fellow’s link attack is Trap Shot,which fires paralyzing bullets that you are able to aim with a cursor.
Super speedy, this chap’s link attack is Thunderstorm, a lightning attack.
If you don’t like these guys you can breed your own using synthesis recipes and locating Dream Pieces.