"I'm not asking for an apprenticeship - but would you be willing to trade me for the basics of magic theory, at least?"

"Yes, I would be. I have never come across mention of your Amestris, and find myself curious what your science is capable of."

"A lot, though I'll note it's rare to be able to use it in open battle like I did - alchemists are researchers and inventors, not fighters."

"Fascinating as that may be, we must keep moving. There are other rifts in the area, and now that we know you can close them..."

"The more I know, the more I can do - but we can talk and walk."

"I'll want a more thorough run down of your abilities, too, so we can predict each other in combat better..."

That can be provided as they go.

Cassandra is a melee fighter with sword and shield, experienced in closing with enemies and controlling their attention. She is also capable of countering and suppressing many magical attacks, and in general making mages have a bad time. Varric, along with his crossbow Bianca, is ranged fire support. He has a few tricks like flash bombs, fire grenades, and caltrops, but those are harder to use in a straight fight on unknown ground and limited in supply. Solas's battle magic is focused around ice, which is what his staff resonates with. He can use that to fire bolts of cold magic, attempt to flash-freeze opponents, and create patches of hazardous terrain or walls to control the battlefield. His skill with healing is not so great that he would attempt such in pitched combat, but he can mend small scrapes afterwards and cast barriers during combat, which are temporary ablative shields, acting like a second skin.

Her specialty is healing, though it requires a lot of focus and is risky to use under fire unless someone is imminently dying. She can, though, given time and space to work, heal just about arbitrary injuries, cure a fantastic variety of disease and poisons... "Cancer is hard," she says, "As are brain injuries, though I can do a lot even there. Try to avoid getting your head broken open, though."

She's also basically competent in moving material around - those earth spikes were a child's exercise pretty much, and she can make large weapons like cannons for ranged fighting, as well as in general pretty arbitrary weapons, and she's trained in firearms, polearms, and hand to hand. 

"...I'd suggest you keep that stuff about cannons close to the chest, Shorty," Varric says. "If you've got portable versions of what the Qunari have on their dreadnaughts- that's going to go over about as well as when the mages broke from templar control." He pauses. "Which resulted in fighting across the entire southern half of Thedas bad enough that the Divine had to use all the influence she had to call this peace conference that exploded, I'm realizing now you may not know. And the Qunari themselves will probably try to have you killed when they hear. Or convert you. Almost as bad, honestly."

" - Okay so cannons are like, more or less outdated technology where I'm from, just to be clear. Like they got pretty cool but cool enough everyone mostly stopped having walls you can hit with a cannon, and then got promptly superceded by the next step in the arms race. But they're really straightforward as far as technology goes, like spears, so they're easy for me to make, while still being pretty easy to use."

" - I'm guessing this means you totally lack firearms though."

"Bianca here is advanced as it gets," Varric says, patting said crossbow.

" - I'll be cautious about what I leave lying around, then."

"That's for the best," he agrees.

"I'll have an advantage though, when I do pull those out..."

"It'll be a surprise, that's for sure."

"Though I'm unsure how easily demons can be surprised."

"They are thinking creatures," Solas says. "They know what they have seen in the Fade. If your weapons are foreign to the dreams they have observed, they will not know of them."

" - Has anyone tried diplomacy?"

"Over the years, I have spoken with many spirits in the Fade. Only a very few have any interest in crossing the Veil to the waking world. They find it unnatural, the fixed and rigid quality of experience oppressive. Those drawn across against their will, as is happening at these rifts, become demons, their natures twisted against themselves. They will reform in the Fade in time, their true selves once more, and be happier for it."

"Is there a way to keep them away from the rifts, then?"

"Not that I have yet discovered. But it is a good thought."

"What are demons made of?" (She has a lot of questions like these, if Solas will keep answering.)

Solas is perfectly happy to keep answering as they go. He certainly has a less religious perspective than Cassandra, even if it's not quite scientific as Bellona is used to. Anecdotal, word of mouth, poetic.

Her deeply scientific mindset is pretty obvious throughout the conversation, and she makes very strange and brilliant mental leaps while simultaneously struggling with 'basic' concepts that are too far from her own framework. 

A most enjoyable conversation.

Eventually, they reach a high bridge which is being used as a forward base for the local soldiers, where Leliana is arguing with a man in white and red robes about the disposition of their forces. The man does not seem to be a military professional.