[Please note: Kind of mirroring the DA game structure to a small degree, but of course these scenarios can be tweaked for the purposes of various RPs :) Hawke's roll can fit a wide range of characters.]
When Hawke first meets Evaris, the elf requests assistance in hunting an assassin that is after him. Though the assassin is captured and Evaris does happily interrogate him, the patron behind the assassination attempts does continue to evade him.
With friendship more or less achieved, Evaris will talk about his blurry recollections of his initiation as a Reaver. The short version is that trio of brothers had rescued him from slavery; they kept him safe, fed him, taught him how to use a blade. Eventually, he decided to become like them. Together, he and the Reaver triplets hunted and killed a massive raging dragon with the most beautiful emerald scales.
They told him to drink the dragon's blood. He did. Everything went black. Hours later, he woke up covered in blood, alone.
Evaris had spent years searching for any sign of them, but not a scrap of evidence came up.
Until finally he had a break-- a half burned piece of parchment from the fire-pit of one of the slain assassins. Half a name, and half an address. Evaris is uncertain and edgy as he (and those accompanying) search the caves and tunnels that snake about the Wounded Coast. Hidden there deep inside the caves, they'll find Dry'din, Evaris' long lost lover.
Dry'din will reveal what Evaris can't remember. The elf went out of his mind after he drank the dragon's blood; he was consumed in a rich green flame that cracked and bubbled his skin and poured out of his eyes. He slaughtered and ate Dry'din's two younger brothers, and tried for Dry'din too, but the warrior had knocked the elf unconscious and ran.
It had taken Dry'din years to decide what to do. Eventually he knew he couldn't let Evaris live; the elf was a danger. He was worse than any in the cult that had worshiped the dragon Andraste; a thing truly beyond The Maker's touch. But Dry'din had loved Aiden (Evaris' name before the Reaver-Ritual) and he doubted he had the will to kill him, himself...
Evaris is understandably a little overwhelmed by all this, and does not notice Dry'din pulling a dagger from his hilt...
B) Let Evaris get attacked
Results vary based on the choice, of course. Evaris then understands how serious Dry'din is about taking his life.
A) Tell Evaris to let Dry'din live
B) Tell Evaris Dry'din must die: Encourage him to kill Dry'din
C) Tell Evaris Dry'din must die: Kill Dry'din for him
Obviously, the tone of events that follow depend greatly on the choices made by the other participating character (Hawke by default, but really, anyone).
Either way, help him stumble through all this shit, and you'll earn this elf's loyalty.