Merrill counts as a blood mage in the first stance, Aveline maybe allowed him to leave but she did not helped him,
Sebastian is looking for Anders.
Hawke may know where Anders is.
Merrill and Aveline are friends of Hawke and companions of Anders.
Thus, Aveline and Merrill are two of the known people in Kirkwall who may have information leading to Anders.
It's really not that complicated.
And when Aveline allows Anders to leave she is helping him. She's captain of the damned guard. It was her job to bring him to justice.
and why attack Kirkall? sending assassins should work better than a war.
Because that won't restore order. Which is also one of Sebastian's goals.
"Slaver?" Who the hell are you talking about?
Loghain.
He sold the Denerim Alienage to Tevinter slavers to fund his war machine because he bankrupted the royal coffers doing things like hiring Crow assassins to kill you and Alistair.
Of course he pretties it up by saying it's for their own good and they're better off slaves.
And about my "flawed" sense of justice, two things:
First; some deuches like Erimond see death as "Haha, I could come back" and second, we've seen that indeed some of them can, bioware seems to like revive the dudes I tried to kill and kill those I didn't wanted, so, no, in Dragon Age I don't see death as a reliable tool of justice, I think is better hit them where it hurts, in Erimond's case, tranquility, Loghain was just perfect: he ended in the order he hated, serving on the country he hated, and ultimately he felt how does it feel being betrayed, and you can finish him with a Nightmare demon, if you run out of ideas for every case, well, left them as a potato like Maria Santiago, that should be enough and prevents them from coming back.
Yes, but what does that have to do with Alistair?
You did say that none of the ways you can kill him were good enough punishments. And in response to a comment that suggested Loghain deserved a second chance. I fail to see how someone can think execution, exile or even worse marrying
Anora shouldn't suffice as punishments for Alistair, while redemption is an appropriate fate for Loghain.
Knowing that you as a
player can metagame a terrible life for Loghain has no bearing on what Alistair, as a
character should consider.
"Alistair buddy, just wait, watching him suffer the next ten years is gonna be sooo much better than just chopping off his head now. And this way I get to save you, Hawke and Stroud's epic mustache!" is not an available dialogue choice at Landsmeet.