Orthenir

Orthenir is a Bosmer in Rootwater Grove

The Flooded Grove
In order to prevent a Daedra invasion, three souls must be killed in the secret library of Hermaeus Mora. The Bosmer soul that needs to be killed escapes, and a replacement is required. The Vestige must either kill Saromir, or have Hermaeus Mora kill Orthenir. Either way, the spirit must then be defeated.