Lightning Field

Final Floor: 30F
Unlock Method: Defeat Entei in Fiery Field
Initial Level: -
Maximum Teammates: 3
Items: Yes
Check Map: No
Opponents Able to Join: Yes

You'll first encounter Raikou in Lightning Field after defeating Entei in the Fiery Field. Your first encounter has it enfuse colour into the Rainbow Wing, but after you have recruited Ho-Oh, you can return there and battle it again. When you do, it will join you and, if you haven't already received it, give you the Sacred Field Camp