Amidamaru

Amidamaru is a heroic ghost from Shaman King who is Yoh's guardian ghost. He is a 600-year old samurai whose numerous killings earned him a bad reputation which was carried all the way to the present time.

Past
Amidamaru was training to be a samurai when he was still very young in order to drive away bandits and protect the orphans he was living with. He always used to break his katana when he was young and his friend Mosuke would always make a new sword. But they were too poor to afford quality steel and Amidamaru was an honorable samurai who refused to steal swords from the corpses and skeletons that were found scattered across the land at the time.

Mosuke, being a very skilled swordsmith, was able to make a sword using his father's knife. Amidamaru was grateful for the sacrifice that Mosuke made, so touched that he shed a tear though Amidamaru pretends that it was the rain and the katana was named "Harusame", meaning "Spring Rain"

When both Amidamaru and Mosuke grew older, they were employed by a daimyo who was impressed with Amidamaru's skills as a samurai and Mosuke's skills as a swordsmith. They worked for him happily, but it did not last long. Amidamaru found out about their daimyo's greed when he asked him to kill Mosuke so that he won't make a sword which would be better than Harusame. Amidamaru was at a dilemma because he owes unrequited loyalty to both the daimyo and his friend.

Amidamaru and Mosuke met at the tree on Monument Hill where Amidamaru told Mosuke what the damiyo told him. At first Mosuke asked Amidamaru to just kill him because an order from a damiyo was an absolute order for a samurai. Amidamaru, being loyal to Mosuke, told him to run away and that he would accept the crime. Mosuke asked him to give him the Harusame so he could fix it up and give it to him later that night. Amidamaru agreed and he gave Mosuke his oath that he would wait for him at that very spot. Someone spied on their conversation and informed the damiyo who ordered his men to kill Mosuke. The men then went up the hill hoping to kill Amidamaru, but Amidamaru killed them all before dying from exhaustion.

Present
After 600 years have passed Amidamaru's tombstone is broken by "Wooden Sword" Ryu. Afterwards, Asakura Yoh takes revenge for Amidamaru by using Hyoi Gattai with him and beat up Ryu. Yoh asked him to be his guardian ghost, but Amidamaru refuses as he is waiting in that cemetery for his friend Mosuke. After Yoh returns to the cemetery, he reveals to Amidamaru that Mosuke was waiting for him to, but passed over after Yoh repaired Harusame. Wanting to pass over himself, Amidamaru is unable to and takes up on Yoh's earlier offer to become his guardian ghost.

When Ryu is first possessed by Tokagero, Tokagero steals Harusame from the museum and wields it against Amidamaru. Tokagero explains that this is his revenge on Amidamaru for killing him six-hundred years ago. Reluctant to do so, Amidamaru and Yoh is forced to break the Katana saying that they did it because of their friendship with Mosuke.

Eventually, they defeat Tokagero, but wonder how they should fix Harusame. Anna points out that she can merely summon Mossuke from the other side and use Ryu's body as a medium. With this the friends are finally able to meet again.