• English / United States: Thaddeus
• Japanese / Japan: タケダ
• Japanese (Romanized) / Japan: Takeda
• Japanese (TL) / Japan: Takeda

Thaddeus is a research worker that works at the very famous Fossil Laboratory in Kojin Town. Alexa requested an interview with him as the laboratories excavation group discovered Amarus and Amaruruga inside a glacier up in the north.

Thaddeus greeted Alexa and Ash Ketchum and his friends and gave them a tour of the laboratory. When Rocket Gang stole the Amarus from the laboratory, he followed in a large truck and helped rescue it.