Could they be setting up Bahubali to be a temporary Indra?
This theory is kinda loose but just hear me out
In the Vedas and Ramayana and Mahabharata, Indra is just one guy. But in the puranas(some believe in them and some don’t) Indra is a title held by different people.
Now in the end of Bahubali 2, amarendra’s face can be seen in the clouds, almost like he is watching over his son
And the name amarendra translates to immortal Indra. (By mixing the Sanskrit words amara and Indra and due to Sanskrit Sandhi rules, the two words become amarendra)
My theory is that amarendra has to temporarily become Indra to accomplish a task. That is why he is teaming up with the asuras to battle Indra in the teaser. And while he does become Indra, in this short time, he will see his son killing bhalaldeva.