SPOILER WARNING: Details about a quest, mission or other Final Fantasy XI in-game storyline follow.
It is implied that he is the son of Yow Rabntah, who found a piece of Magicite during the Multinational Expedition and used it to construct the Bow of Light. However, the Magicite within the Bow corrupted Yow Rabntah, causing her to instigate the beginning of a violent and bloody civil war; she was hence branded a sinner, and Leko now carries the same burden. As a result, Lehko Habhoka continues to be hunted by Shikaree G, presumably to pay for the sins of his mother.
When Lehko first arrived in the Middle Lands, he was captured by Shikaree G and sentenced to death. The Shikaree tied him up and threw him into the frozen waters of Qufim Island to drown. However, he was revived by Cait Sith Deich (who lost her body through unknown means and had to fuse with Lehko to preserve herself) and later met Robel-Akbel. Forging an alliance with Robel, as his military tactician, Lehko gained access to the seat of Windurst's power. Lehko's true motives were not the safety of Windurst however, but revenge upon the Mithra who had wronged him. In the end though, Lehko decided to protect Windurst by defeating the rogue beast Fenrir; but as a result he was grievously wounded. Cait Sith Deich departed from him and left him to die, as he had lost his will for revenge and considered his work done. However, later Lehko is again revived (presumably by the work of a Cait Sith) and decided to leave the Middle Lands. He is last seen aboard a ferry to lands unknown.