Underground Man

The Underground Man (ちかおじさん) lives in Eterna City. He is the father of Byron and the grandfather of Roark.

In the games
When the first meets him, he gives them the Explorer Kit. The other NPCs in his house describe various aspects of exploring the Sinnoh Underground.

He also gives a series of tasks, each with various rewards when they are completed:
 * Use the Explorer Kit and go to The Underground
 * Dig something out of the wall
 * Plant a Sphere in the ground
 * Dig a Secret Base
 * Decorate a Secret Base
 * Capture a flag from another player's Secret Base
 * Capture five flags from another player's Secret Base
 * Capture ten flags from another player's Secret Base
 * Capture fifty flags from another player's Secret Base

In the anime
The Underground Man first appeared in A Grass Menagerie! while Team Rocket was exploring the Sinnoh Underground. He convinced Jessie, James and Meowth to dig up spheres and shards for him from the Underground, and fed them as a way of thanks. However, while they ate, he fled with the treasures.