Guilt, Pride, and a little Bitterness on the Side
Long post - evaluation/exploration of Solas and a more negative-leaning take of his character. (coming from a diehard solavellan fan)
Something I've not really seen in the DA fandom, is the fact that, regardless of approval level/romance, Solas must just really hate Inky.
Allow me to explain, my dear lovelies:
Looking at it from Solas' pov; his plan for the orb at the beginning of the game goes to hell real fast. Hundreds, if not thousands of people die (horrifically, painfully, screaming) because of a situation He created.
But it's not just his fuck up/miscalculation - it's Inky's. The one survivor of the explosion, the one who foiled the plan to tear down the veil, the one who stole his power (we can consider it was an accident/coincidence, and Solas probably recognises it as that, but damn. If it were me in his shoes, I would be rather malcontent about that).
Yes, we may also consider this is a lucky break for Solas - he has another option laid out before him, and all he has to do is make himself appear useful and relatively harmless to keep close by for the eventual snatcheroo of the foci.
There's a messed up connection between Solas and the Inquisitor there - every death, every ounce of suffering and heartbreak is both of your faults. You're bound in blood, as it were - for an catastrophic event neither of you anticipated.
I imagine he has a great deal of guilt over this throughout the game - he's fucked over the world again - and he's got some random person caught in the middle, someone he's forced into a position of power (someone who is either a horrible person ready to take power, or a perfectly fine person who is likely to do horrific things that will tear them apart inside and out). He's corrupted you, essentially. He's not only harmed/killed countless people. He's made you the one responsible, he's making you into a puppet, puppeteer, and a monster. -- Again, from his perspective, he fully expects that power corrupts absolutely - he's hurting you on multiple levels.
Additionally, we're going to have to look at this on a broader level to get a grasp on the scale of this.
The events of the Conclave - tearing open the veil, causing rifts across Thedas - it's damaging the world and the Fade (sending animals into a frenzy, bringing demons through, making whole areas uninhabitable). Physical beings are being put in mortal peril, but we have to consider that so are spirits.
We know Solas favours the Fade/Spirits to the waking world and mortal beings. He outright states it on several occasions.
And we know that the Breach and the rifts force spirits and demons through, and drive them insane as a result (even Cole appears to have panic attacks over the rifts on occasion).
Allow me to put it more tangibly;
I think that chapter of the story is what highlights his bitterness/guilt the best - if not his entire character.
All I can ever think during this scene is this; if Inky hadn't been at the Conclave, his friend wouldn't have died. If Solas hadn't given his orb to Corypheus, his friend wouldn't have died.
It's his fault she's gone, and it's your fault too.
I'm always reminded of this scene at the end of the game when I think of Solas and his mentality. In this scene, he's- well- this man is fucked up.
He says 'it is not your fault' and you can tell he's meaning it's his. But I can still see it in there; he wants to blame Inky, he wants it not to be his fault, and the voice acting really convinces me of that (bless you Gareth David Lloyd). But he can't, because it all comes down to him and his countless mistakes (and terrible luck, like seriously, I think the universe has a personal grudge against this man).
That expression says guilt, shame, regret, bitterness. This is a man whose every effort has proved in vain- all the suffering, death and irreparable destruction. Everything he's done to you, it's all his fault - because he thought he was the smartest guy in the room, he's the only one who can fix everything because he's so prideful and experienced.
Now consider if you were his friend, if you were his goddamn vhenan. It cuts real deep.
Solas is a man who's been tested time and time again, and every time he's been found wanting.
He's a complex, compelling character (that I love absolutely), and he's objectively a terrible fucking person, and he knows it. Everything he touches burns, everything he tries to fix he makes worse, any advice he offers eventually turns bitter, and he knows it.
I'll leave you with this;