Fasendil is in charge of the Imperial soldiers at the Rift Imperial Camp. He is an essential character, which means he cannot be killed. If the Rift is taken by the Empire during the Civil War, he will instead be found in Mistveil Keep, located in Riften.
Fasendil hails from Cyrodiil. He is the son of two travelling Altmer merchants who settled there. He grew up in the city and, once he came of age, joined the Imperial Legion to see more of the world. However, he claims he has seen much more than he bargained for.
If the Dragonborn is not a Nord, a dialogue option is available regarding an observation that the local Nords don't like outsiders in their lands. Despite this, Fasendil feels Skyrim and its people are still a part of the Empire, and, as such, are entitled to the Legion's protection.
Even though he is an Altmer, Fasendil has an outward disdain for the Thalmor. The origin of such stems came from his station in Hammerfell's city Sentinel in 4E 42, during the Night of Green Fire. Thalmor Mages were sent there to capture Altmer dissidents who'd escaped execution from the Summerset Isles.
When he was on his way, a huge explosion of magicka erupted from the refugee sector of the city as the Thalmor Mages and the Altmer dissidents fought each other. When Fasendil arrived at the scene, the entire refugee sector had been destroyed as a result of the battle.
After an unspecified amount of time after this incident, Fasendil was stationed in Skyrim by order of Emperor Titus Mede II to keep an eye on the Thalmor.
Why did you join the legion?
"My parents were wandering merchants eventually settling in Cyrodiil, I must have inherited their wanderlust. I joined the Legion to see the world, I know that's just one of those things that people say, but it's completely true in my case. It wasn't long before I saw more of the world than I bargained for."
You're from Cyrodiil? What's it like back home?
"Home? Home to me is a hot cup of ale at the end of the day, and 5 minutes without someone needing me. Cyrodiil is a beautiful place with diverse people and histories, so too Hammerfell and Skyrim, and every other place I've been. Don't get me wrong, every country has its dark corners, but that's why we're here, to bring order and civilization, and to protect the people."
Not everyone seems to want us here.
"Ulfric and his thugs are stirring up trouble for their own agenda, the Empire is the only thing keeping the Dominion from walking all over Skyrim. It matters little if some people here are ignorant of that truth, they are still citizens of the Empire, it is our solemn duty to protect them."
Sounds like you've seen you're fare share of hardship.
"The life of a soldier is full of hardship, that's nothing, but they send the Legion to places that have become too bad to be settled without violence. What's hard is seeing people warped by evil, and I've seen the face of evil, it was in the air above Sentinel on the night of Green Fire."
What happened on Green Fire?
"Back in 42 I was stationed in Hammerfell, on leave in Sentinel, trying to track down refugee family members who were trying to escape persecution in Alinor. Suddenly, an explosion of magic in the refugee quarter. Thalmor mages were attacking Altmer dissidents, who were resisting with magic of their own. I ran with some other legionaries who were stationed there, but the entire quarter was a smoking ruin by the time we got there, everyone was dead, wholesale slaughter. The Dominion, not content with killing dissidents of their own back home, came to Hammerfell to finish the job. We're supposedly at peace now, but I put in to be stationed here to keep an eye on the Thalmor, I have a feeling they're behind this unrest here in Skyrim."