Whis is an NPC that appears multiple times across all worlds excluding Namek.
Whis (Central City) - Located in Central City inside a small building similar to Elder Kai's building with a purple roof. Interacting with him prompts the player to buy some of his Rare Moves for 10,000 Zeni.
Whis (Beerus' Planet) - Located on Beerus's Planet in Space, just in front of the player upon landing. His role has been switched to that of a Quest Giver that offers the player 2.5 million EXP and 2,000 Zeni as a reward for defeating Beerus at 50%.
Whis (Future) - Located close to Vegeta in the mountains south of Central City. He still serves as a Quest Giver that offers 8 million EXP and 4,000 Zeni for defeating Vegeta (SSJB).
Whis (Tournament of Power) - Located on the rightmost side of The Lookout. His role is that of a minor NPC, as interacting with him merely tells the player that they must be Level 400 to participate in the Tournament of Power.
List of Rare Moves
See Rare Moves.