User blog comment:B214/Volume 22 spoilers/@comment-205.197.242.180-20160825004852/@comment-9595671-20160825011033

I'm not sure if he'd side with either side since Issei doesn't want war, especially after how Azazel defined it during the peace conference to him.

Though I would say if he had to choose a side that Shiva does seem more likely. Indra's actions haven't beeen the best, he told Azazel he'd kill Issei if he became a challenge to his spot in "heaven" and I think I recall hearing this arc is gonna bump him to an antagonist.

At the same time, Shiva has had some shady actions of his own lately.