Buck (Japanese: バクBaku) is a character that first appears in the Fight Area.
He can join the player during an event in Pokémon Diamond, Pearl and Platinum. He asks the player to join him to the top of Stark Mountain because he underestimated the strength of the wild Pokémon located there. He then follows the player around, keeping the player's Pokémon healthy. The player must help him find the 'treasure' of Stark Mountain. After getting to the room where the treasure, and later Heatran, is found, he takes the treasure which appears as a stone in the games. Afterward, he can be found in his grandfather's house in the Fight Area where he is told to return the stone to it's rightful place. Later, he can be found in Sinnoh's Battle Tower competing against the player. He specializes in Pokémon that have high Defense/Special Defense capabilities.
Buck appeared in DP181 Bucking the Treasure Trend. Ash & co. were on their way to Lily of the Valley Island - Headed for the Sinnoh League. Buck however was on the way to a closer location named Dandelion Island. As Brock suggested Buck is a Treasure Hunter alongside his partner Baltoy. Buck searches for Rare Items and uses Baltoy's senses to find them in difficult situations. Ash and friends helped him find the treasure of Dandelion Island - Ancient Pottery, guarded by a powerful Claydol which (with Ash's help) Buck defeated and captured. Buck appears to be a Treasure Hunter. Buck wants to become an Archaeology Professor, his hobby of being a Treasure Hunter helped him to realise his dreams and potentials.