I have to wonder who here noticed this... That in DA's iconography more often than not the Fade and magic itself is represented by down-turned triangle?
Solas draws down-turned triangles frequently on his murals, each time it's something in the background or in empty spaces that represent air and/or sky - it's stuff that radiates from above and drops towards the Earth.
Interestingly enough, the dwarves are oftentimes shown in company of upturned triangle - more then likely representing Earth or Stone.
Th the Earth and the Fade is something of an opposite, but equivalent force.
Even more interestingly two of Solas tarot cards have rhomboids - so a merge of both.
At fist I thought it was supposed to represent the Veil - either his knowledge of it, or (post-Trespasser) that he's its creator. But now that I think about it, I think it may as well represent Solas as an agent of balance (which, given the ying-yangish iconography surrounding him, is far from far-fetched); the one that is supposed to bring it back to the world, even if violently.
Another interesting thing to consider is that the mysterious Executors' symbol is a downward-pointed triangle with two wavy lines drawn through it - I assume therefore that they're either planning to do something magic/Fade oriented, or perhaps await the time when magic/Fade is permeated with... something else. They do after all say in a letter sent to Inquisitor that "they prepare for the day and hold vigil"... I wouldn't be surprised if they actually await the same day Solas does (totally betting on it being some kind of celestial event), in order to realize his plans.
Which, to me, means that the chance that we'd see them in DA4 is more than likely - they may even be pretty important.
I wonder in what role we'd see them though. Allied with the Inquisition? Allied with Solas? Someone else? A while ago I speculated that our next PC might in fact THEIR agent - and actually, I still think it is within realm possibility. A lot of us assume that we my as well be allied or picked as agents of Inquisition, myself included, but how interesting it would be if we were actually Executors first, and then we might decide who we ally with? Or perhaps we'd be able to pick a side during character creation (Inquisition agent, Fen'Harel agent, Executors? Maybe they'd even come with their own origin story or individualized crit path?) and then decide which side we're actually supporting?