The trailer contains all the secrets from the previous films, let's break it down.
Ant-Man and the Wasp: Quantumania trailer breakdownScott Lang is honored by the employee of the century because he saved the world and the child has Ant Man bags but they know Ant Man as Spiderman because both avengers have the same color of costume.
Cassie langIn the next scene we see Scottlang's daughter who is Cassie Lang, she is very interested in the quantum realm because her mother's mother (Janet) was in the quantum realm for decades and she didn't grow older because there 5 years was equal to 5 hours But Cassie's curiosity got her into trouble because she was sending a signal to the quantum realm that is dangerous.
The quantum realmBy the time Janet found out that the cassie is sending signals to the quantum realm, everything had gone out of hand and they all reached the quantum realm. where we see many different portals, they can be from other dimensions or portals of time travel or multiverse Which Kang uses for his journey.
Many creatures we saw in the quantum realm and they look like they fear Kang Janet has already clarified that it may be the Secret World or the micro Universe which may be the Kingdom of Kang.
KrylarIn the next scene we see Bill Murray playing Cryler, the first time Kryler was seen in the Incredible Hulk comics in which Cryler's body color was green but this trailer shows Kryler's normal complexion.
Machine shotHere Kang is putting a bell in the machine around which yellow light is emitting, This scene reminds us of the Galaxy Vol 2 movies in which Rocket stole batteries from the Queen's Empire and the Queen searches for Rocket to return those batteries, this scene remind me of those batteries. So it makes it clear that Kang has many technologies that are already applied in other films.
The Shang-Chi RingsIn the next scene we saw the rings as a structure, if you saw that there was an energy essence in between these rings, the same energy essence was seen in the Sangh-Chi rings.
So it could be Sangh-Chi's rings, Miss Marvel's bangles or a technique made by Kang himself.
The signalsSomewhere in the post scene of the Sangh-chi movie the rings were sending signals, there was also Captain Marvel, and said we can't find where these signals are going.
If these signals are transmitting in the real universe then Captain Marvel may be trying to figure out where these signals are going. Now this trailer clarifies that those signals were transmitting in the quantum realm And it was already made clear by the Janet that transmitting signals in the quantum world is very dengerous, as Kang could have known.
The artifactshere the artifacts are shown may be Miss Marvel's bangles, sangh-chee's rings or Wakanda's vibramium,
The EternalsIn the next scene a man is opening the door, the design of that door is very similar to the one we saw in the movie Eternal This scene makes it possible that Kang is trying to assemble multiple techniques at the same time.
The Ant-mansAs Schottlung was running in the realm, here he saw another version of himself who was mortally slain, These types of antman were from the other universe by which Kang is trying to show Scottlang how Kang killed the other types of Antman
kang the conquerorKang is the menacing form of his other forms, Mephisto in the Loki series has already cleared Kang's cruelty. Kang has the same form as shown in the comics, according to the comics Kang can travel to the future and the past.
Kang's army runs on Quantum Energy which is a blue light, if you noticed, the same blue light was reflected on the helmets of the avengers when they time travel This technique can only be adopted by Kang, Kang is from the future so it may be possible that Kang used Tony Stark's time travel technique and proceeded to use it against them.
In Avenger Endgame it was made clear that if we change the past by traveling into the past the future will not be the same as before, but the laws of physics and time differ according to the multiverse, and Kang may have the power to bring the power of the other universe in the another universe, if it happened it would be dangerous, and it might even be possible that iron man comes again in the same timeline.
So far Kang has the power to travel in time but after gaining more technology Kang can have the power to travel in the multiverse, which we have already seen in 'Doctor Strange Multiverse of Madness