Beem-Ja

Beem-Ja is an Argonian mage in and is encountered near Ironbind Barrow, along with his fellow companion, Salma.

Background
Through Salma, he enlists the service of the Dragonborn in order to find Gathrik's tomb.

After locating and defeating Warlord Gathrik, he then talks to you and attacks you, saying that in "order for him to fully absorb Gathrik's power, a blood sacrifice is needed".

Letter to Beem-Ja
Upon killing Beem-Ja, a letter can be found on his body. The letter indicates that Salma's father does not trust him, but accedes to his killing Gathrik in order for him to obtain the "book [he wants] so badly," on the condition that he ensure his daughter's safety. This book turns out to be the 2920, Frostfall, a Conjuration skill book.

Bugs

 * Sometimes Beem-Ja will not have equipped his robes and he will fight naked.
 * Sometimes Beem-Ja will disappear in combat if not escorted to the end and protected.
 * Sometimes Beem-Ja will not revive Gathrik, which makes the fight much easier.