pigeon

while we are told straight up in the trailer that Aaravos wants to bring about eternal night and unleash the spirts of the dead, but why? for what end goal? my theory Aaravos has three main objectives: 1 to take revenge on those responsible for imprisoning him. 2. to upset the Cosmic Order and 3. to be reunited with his daughter.

the reasoning behind his first goal: revenge on those responsible for imprisoning him. we know Aaravos clearly hadn't enjoyed his years of imprisonment and has spoken on several occasions about his distain towards those responsible (s3 ep6, s4 ep4). in the trailer we see to clips backing this up.

this clip is likely set the underground location where Akiyu gave the dragang the map and it appears that she is... resting. Akiyu is the one who made the prison and one of the only few people still alive who had a role in Aaravos' imprisonment.

(ignore Callum I'll get to him later.) the background of this shot appears to be mushrooms so I assume it's the home of the mushroom mage who is currently taking care of Zubeia, the only other person alive (as far as we know) who had a part in Aaravos' imprisonment. some sort of fight scene may take place here as Aaravos attempts his revenge on her.

2. while it's not yet clear in what exact extent the cosmic order controls event it is evident they have a strict idea of magic, who and how it should be used. Aaravos rising of the dead goes against the natural order of things- while also being useful grunts to do his dirty work. their existence likely disturbs the cosmic order. We know specifically that the cosmic order doesn't want magic in the hands of humans so if Aaravos invented dark magic it was to further this goal.

Even though dark magic allows humans to perform a type of magic it is consider unnatural as it's not a primal source. They punished Leola for giving humans primal stone which allowed them to preform primal magic. This is where Callum comes in, after Aaravos was freed I saw no point in Aaravos needing him as part of any plan until I though up this goal. Callum is a human who has learned primal magic, seemingly on his own. Callum existence is a big upset to the cosmic order and proof that humans could learn magic on their own, Leola actions were not solely to blame for humans having magic.

While this upsets the cosmic order it also proves them wrong about Leola potentially leading them to take back their ruling connecting to the third goal.

(there is a chance the cosmic order is long gone at this point given they appeared +300 years before the main story)

3. I feel i don't need to justifie this goal with much edvidence as Aaravos tells us how his daughther is teh primary motivation for his actions. I'll keep this brief. I see tow ways which he could go about this goal, one he uses the previously mentioned goal to get the cosmic order to bring her back or using his eternal night spell to bring Leola back form the dead. A spell to bring back an immortal probably requires some large complicated ceremony which he may enact over season 7.