Solas appears, at least initially, as a rather aloof, mysterious elven man that seems to have no real history or paper trail with regards to where he's been and what he's been doing. Loathe to answer much about his own personal life, especially with people he doesn't know or is disenchanted by because of their heritage, he is far more comfortable spending time talking about the things he finds most important; magic, the Fade, elven history and the power surrounding all the old stories. There is, of course, far more to Solas than the initial impression.
He is incredibly critical of societies that damn or limit personal expression or freedoms and he isn't shy about expressing it – Solas is an avid believer in the ideals of liberty and loathes slavery on all levels, choosing to be very vocal on all counts. As Fen'Harel Solas, by all accounts, sealed away the old elven Gods for their sins, their pride and for keeping slaves and marking them as such (hence why, in the romance, Solas uses the vallaslin as a means to distract his Inquisitor from the truth of who he really is). To Solas, freedom isn't a choice people ought to have – it's a right, something everyone should be born with, and he often comes to verbal blows with the companions over these matters, especially the Qunari Iron Bull and the Tevinter Dorian Pavus.
His critical nature isn't limited to just liberty, however. Solas is passionate on a number of levels on many topics that come up during the game, but most certainly the idea of what the Dalish Elves have become in Thedas. The history that the Dalish believe is something that Solas has learned to be false – either because he is Fen'Harel or, as he says when asked, because he has walked the Fade and seen the memories of the true history of his people. While he is neither a Dalish nor a City elf he has attempted to offer his knowledge to his people only to be shunned for it; since then he regards most elves as foolish, ignoring the truth of their history to enjoy the myths and falsehoods that they cling to. He is smart and knows what he is talking about, knows what he wants to offer to the people, but having been rejected so many times has left him disillusioned with the Dalish.
His idea of a good future is the idea of progress, of repairing the mistakes he made in his youth and bringing about a better shaped Thedas. It's one of the reasons why he is so highly critical of the Grey Warden order; while they're regaled for their courage and their ability to stop the Blights that attack the lands Solas sees them as ineffective, as not having done their duties properly – and, during the events of Inquisition, as having given into the power of ritual to summon and harm spirits and demons far too easily. For all that he tries to educate and aid his companions Solas is, at heart, a critic, bent on shaping the world in an image that he sees as best. For all that it appears, Solas doesn't see the Wardens as progressive, as worthy of credit; his main focus is undoing what he did in his youth, to free the elven Gods from the trap he had ensnared them in, and the Wardens are not doing their own duty to Thedas.
But Solas attempting to help the world doesn't mean he is somehow above it – there is a reason his name means 'pride' in elven. Often it seems that he considers himself to be above others, more educated and more worldly, knowing more because of his ability to walk the Fade lucidly. His criticisms come easily and he is quick to damn those that don't heed his advice or warnings, often requiring great lengths to encourage him to come back to a more companionable state once something he disagrees with has been achieved. Continually doing things he disapproves of will result in a far more sarcastic and rude version of himself, lowering his approval and expectations for his friends and Inquisitor alike; he won't bother to hide his disdain and will be vocal about how far he thinks you have fallen.
Despite being stubborn, opinionated and, at times, a walking, talking frustration, Solas is relatively easy to get along with. The best and easiest way to make friends with him is to simply ask him questions, to show an interest in the world around you – be it the Fade, magic, spirits or history itself. His fondness for the Veil is an obvious forefront to any conversation and Solas is always keen and happy to answer questions and tell stories about his experiences, the things he has seen and learned. After being dismissed by his people and ignored by the rest of the world, seen as nothing more than a Hedge mage, it's obvious why he would take such delight in offering up memories and stories to those that would actually sit down and listen to him.
One of the fundamental aspects of who Solas is, however, is his secretive nature and his dislike of sharing himself or his history. He makes idle remarks about his youth, his part and the things he has seen and done but, if asked directly, often finds a way to avoid the question or change the topic entirely. If he lets something slip about his past he becomes somewhat nervous and guarded, careful about letting on more than, perhaps, he feels like he ought to. This is primarily because Solas is Fen'Harel, one of the old elven Pantheon and regarded as the traitor that locked the elven 'Gods' away in the eluvian centuries before. His past is a part of elven history and mythology and revealing that he was, in essence, a God, would no doubt be problematic.
This does add a certain aspect to Solas' nature that's really only clear once the player realises who he is. Solas is, throughout the game, secretive and quiet when it comes to who he is, but he is always very well informed about aspects of the battle they're fighting; he seems to know what to expect, what to prepare for and what they are facing. This is because it is Solas that gave the game's 'big bag' the power he needed to enact his plans by offering up his Foci, an orb that was, at the time, dead. By using Corypheus to power his orb Solas was hoping to be able to use it to free his fellows from the prison he had put them in, realising the mistake he had made so long ago. This is his motivation throughout the game and explains many of his actions; why he is loathe to reveal who he is, why he acts so distant and prideful at times and why, during the romance, instead of admitting the truth he chooses to lie, instead, and allows himself to be a coward.
This cowardice only continues once Trespasser comes to and end. Solas, for all his strength, wisdom and foresight, failed to recapture his own power and, in turn, allowed it to cause a breach that almost destroyed the world. When he gets his power back he doesn't intend to use it for good - at least, not a 'good' that most others would accept. He wishes to tear down the Veil he himself created, separating the world from the Fade, and restore the world to what it once was at the cost of the world itself. While, at first, he appears to be confident and set in himself an Inquisitor with high enough approval can break him down - and we can then see that he does have many regrets. The Inquisitor had taught him that there are good things in this world and he hopes, almost desperately, that they can find a way to stop him, to find an alternate route.
