• English / United States: Case
• Japanese / Japan: クレイ
• Japanese (Romanized) / Japan: Clay
• Japanese (TL) / Japan: Clay

Case works as the assistant to Professor Marble at the Tesseed Laboratories in a port city near Tachiwaki City. He took Ash Ketchum and his friends as well as Georgia on a tour of the facility as they wanted to learn more about the moss that could increase a Pokémon's powers which they research there. He told them all about the different moss and where they rocks and stones they use came from. He unfortunately had to tell Georgia that they hadn't discovered moss effective on Ice types yet but he told her that he would inform her as soon as they did.

When the moss started to overrun the laboratory, Case told everyone to take refuge in the control room down in the basement. He then informed Officer Jenny (Unova) about the situation and was concerned about Iris on the roof.