Amidamaru is a key character in the anime series Shaman King. He is a samurai spirit who becomes the guardian ghost of Yoh Asakura, the protagonist. Amidamaru is renowned for his exceptional swordsmanship and strong sense of honor. Throughout the series, he supports Yoh in battles against other shamans, using his skills and wisdom from his past life. Amidamaru's loyalty and noble character make him a valuable ally, and his past as a legendary samurai adds depth to his role in the series.