Bayushi Baku

Bayushi Baku is a spirit that remains in Rokugan after losing his memory to the Lying Darkness and remembering only that his duty is to serve the Bayushi family. He recognised Bayushi Sunetra as the Scorpion Clan Champion after seing her being recognised by Churetsu, the Celestial Sword of the Scorpion Clan. Some time after, he accepted to help the Scorpion Clan Daimyos to fight against the Gozoku and find Bayushi Atsuki, the Leader of the organization.

Baku's loyalty
We don't know so much about Baku's live. His history and memory were destroyed by the Lying Darkness. Baku was a loyal samurai. Baku was not serving the Scorpion Clan Champion or the Empire. He served only the Bayushi family, and his bonds of loyalty remained beyond life and death. After his death, Baku didn't go to another realm. He remained in Rokugan to continue his mission, and serving in his own way the Bayushi Family. His view of the facts is distorted through a mask of death and pain, so only distinguish between two positions: loyalty and disloyalty. For him, the other people are either friends or enemies. If he see someone as a friend, he will do nothing. If he see someone as an enemy, he will kill him.

The Clan War
During the Clan War, when the Scorpion were outlaws, Baku was a vengeful spirit. He roamed the Scorpion Provinces murdering any Imperial Legionnaires he found. He left widows and orphans in his wake with no remorse.

War of Spirits
After some years in which there were no news about him, Baku appeared at the height of the War of Spirits and offered his aid. He gained the trust of Hantei XVI and led him into the trap of Toturi's followers at Beiden Pass, helping to save the Empire from the armies of the Steel Chrysanthemum

Major References
Unfinished business: the Scorpion - by Rich Wulf