As if the Red Templars weren't already terrifying in the power they wield, the Behemoth bears the remains of a templar's armor. Any templar who ingests Red Lyrium is in danger of becoming one of them. And judging by Meredith's fate, it is doubtful they can survive long even then.
The screenshots of Emprise Du Lion show a tower that has Red Lyrium growing out of it. It's not just in the deepest reaches of the Deep Roads anymore, it's on the surface and it's spreading.
As mentioned below, Red Lyrium is lyrium tainted by the Blight. The Red Templars are essentially ghouls/darkspawn.
And how are the Templars getting their lyrium fix when they've cut ties with the Chantry? The Carta is fully willing to provide, especially after they stumble across a massive supply of Red Lyrium in the Hinterlands. The ones calling the shots there aren't in prolonged contact with the lyrium either, so every case that turns out like Bartrand is chalked up as someone trying to make money on the side.
The Breach, the cataclysmic event that tore the Veil asunder occurs during Peace Summit between the various factions in Thedas. As a result, thousands of the people who were at ground-zero were reduced to char-grilled husks, their barbequed remains still frozen either in mid-scream, running or cowering from the devastation. And the Inquisitor is the Sole Survivor of this event.
What has been shown of the new demons indicates that they're pretty creepy, with their weird teeth and mummy-like complexions. The Fear and Terror demons certainly live up to their names.
As the game progresses The Breach becomes larger and larger. Trailers and gameplay videos imply that later on in the game the Breach is large enough that it covers most of the sky above Thedas. The sun is blotted out completely, the skies turn a eerie green, and the floating islands you see in the Fade start to fill the sky.
In the Bad Future showcased when recruiting the mages, Leliana looks like an old woman after only a year. There's a reason for this - in his efforts to fight the darkspawn taint plaguing his son, Alexius had been taking living tissue samples from subjects, particularly those that showed high resistance to it. Leliana was the most promising one.
The fact that the other two companions and have obviously been infected by Red Lyrium, and are already losing their grip on sanity. Poor Fiona has a massive deposit of the stuff growing out of her and into the walls of her cell, pinning her in place.
The ocularium that you use to search for the shards are made of tranquil skulls.
'The Enemy of Thedas' trailer is a dark, most sinister twist of the previous trailers. Before, it was continuous glorification of the Inquisition and their cause to save the world, but here it's all turn on its head; The Inquisitor and allies are all struggling and being beaten up by the various enemy factions, especially the demons, showing just how completely outpowered and outnumbered we are in this war, and our likely antagonist, the Elder One, whoever of whatever it may be, is the real one who controls the battle, not us.
In Dragon Age Keep any character that dies is represented by a broken skeleton imposed over their silhouette, including family members and love interests of previous Player Characters.
Dorian's father tried to alter his son's sexuality through a blood magic mind control ritual.
Apparently Red Lyrium is infected with the Blight. Yeah, the darkspawn can corrupt the very basis of magic, too. Including that time when they didn't exist in the Primeval Thaig.
Also, because of that spoilered fact, this means that Lyrium is alive, as minerals aren't susceptible to the Blight. That this was discovered after at least a millenia In-Universe is worrisome.
Cole is almost always serene and equanimous, in line with his unearthly origins. But... he is infuriated when he finally tracks down the Templar who condemned the original Cole, a mage at the Val Royeaux Spire, to a maddening agony of a death by leaving the mage in an oubliette-like cell to starve. All of the companions demonstrate OOC Is Serious Business at some point, but Cole's obviously being on the edge of an Unstoppable Rage is likely the most frightening.
The demon of Envy, which serves as the boss at the end of "Champions of the Just." In addition to looking like something that crawled straight out of Silent Hill, it can flawlessly assume the appearance and mannerisms of ANYONE. It does this by invading the minds of its victims and observing their reactions to nightmares that it creates. It then uses these observations as reference material for masquerading as the victim.