Indra thought that Kisuke would be coming to their side since Evies are seen as 'villains' by the public and he had a previous encounter that almost killed them. While he knows that Kisuke doesn't view things as black and white, he's still confident that his choice would be the Etouldes because Kisuke is not alone. He may be fine being called a villain or evil, but that doesn't apply to those who are around him. Indra knew exactly how important his lovers were to him and wouldn't hesitate to use them to win him over.
And why would Shiva think that Kisuke could possibly move towards Evie's side while knowing that they are branded as 'villains'? Because he knew something else that those on Indra's side didn't know. The Etouldes won't tolerate Kisuke, Yoruichi, and Aika's existence. Although they allow weaker abilities like summoning spiritual creatures or body strengthening through Spiritual Power, they won't allow the development of unique abilities that directly come from the souls.
When Shiva was trying to make a choice between the two camps, he tried gathering as much information as possible, utilizing every bit of his power to do so.
Fortune smiled at him and he was able to peel away some fog covering their adversaries. The Evies paint the worlds as they see fit and Etouldes tries to do the same while pretending to stop the former in the name of justice, Shiva has seen both of them.
He also figured that the Evies find the Soul Gears fascinating and the Etouldes wanted to eliminate them at all cost. So if that's the case, siding with the Etouldes would just be placing a timed bomb beside him, Shiva thought.
With those in mind, he manipulated both sides to gain as much advantage as possible which included instigating the Etouldes to attack Kisuke's camp and causing one of their members to fall into critical condition so that their group won't be able to work with the Etouldes.
"While we're at it, why don't we properly settle everyone's alignment right here and right now? It would be disastrous if a few people were to suddenly jump ship, isn't it?"
As soon as they heard Kisuke speak of this, they all looked at each other and thought that it was really a good time.
The first one to respond was Indra who raised his hand and said, "Make a vow. To those who won't do it, forget about leaving. I'm destroying you."
Shiva also silently raised his hand and the next instant, two distinct Magic Circles appeared on the two groups, containing their insignia and their Divine Power.
Every other leader looked at each other before a few of them started shuffling between the two groups. While there are virtually no changes in their size, they've exchanged a few members who intended to spy from the inside.
Indra and Shiva looked back. It's a shame that their insiders were gone, but that's still a lot better than knives on their backs.
The Magic Circles descended on their groups and soon, the members were made aware of the contents of the vow. As the vow only restricted their allegiance between Indra and Shiva, they all soon agreed by raising their hands and saying that they'd be aiding either Indra or Shiva in their quest to best the other.
It was a simple ritual but it's immediately binding. The moment they betray their vows, their cores would be destroyed, reducing them into powerless mortals. For most of the prideful Deities, that punishment was way worse than death itself. They can die with dignity, but they'll never allow embarrassment.
Kisuke's smile grew wider as all this happened. He couldn't care less about how they aligned themselves as what they are doing is just the same thing. Collecting soldiers to fight their war. Obviously, Kisuke doesn't want any of that.
But as he expected, the two sides won't allow him to stay out of it, "Now that a clear line has been drawn, it's time you make a choice." Indra stated.
As soon as Kisuke started shaking his head, killing intent instantly appeared within Indra and Shiva's eyes while those behind him were a mix of worry, amusement, and hostility.
"You're giving me way too much credit. We're just one faction that isn't even that big. What difference am I going to make?"
"If you truly believe that, then I truly overestimated you." Shiva replied, "Stop joking around. You know what you're capable of and that's the very same reason that we can't leave you alone. Come to my side and aid me. You have no hope of surviving on Indra's side."
Indra's eyes sharpened and didn't say anything. He knew Shiva and wouldn't just say something like that because even if he's confident that he could destroy him easily, Shiva wouldn't be declaring it, '...Did I miss something?' He turned to one of his trusted Deity and gestured at him. The next moment, the Deity nodded and left the virtual world.
But contrary to Indra's reaction, Kisuke's expression didn't change, still as confident as ever, "I appreciate the concern, but aren't you guys misunderstanding something?"
"Misunderstanding?" Shiva asked. It was his turn to make a serious face.
Kisuke turned back and started walking away from everyone, "We're playing on the same field, yes. But since when did you guys think that I'm a chess piece?"
"Are you saying that you're actually the third player?" Indra smirked, "You know what? I wouldn't actually mind that. Just beware that you might get attacked from two sides at the same time. It would be a shame for you to drop out as soon as you step up." He's insinuating that, unlike the neutrals who would like to stay out of their conflict, Kisuke was someone who wanted to actively oppose them.
That threat of Indra against the Ouroboros Academy was further realized after both he and Shiva gestured to their 'pawns' and they also left as soon as they received their instructions.
"Player? So you really are misunderstanding me." Kisuke just chuckled, "Hmm... Let's see... If you really want a label, then I'm more of a referee or an umpire."
At that moment, Indra, Shiva, and the other Deities recalled something very important that they'd forgotten until now.
Taking delight in the expressions they were making right now, Kisuke continued, "If I can pause the game, I can also resume it."
Shiva's full-blown killing intent immediately drowned the entire space and said as his face twisted, "You wouldn't dare!"
"Aw-shucks~ You just had to say my favorite phrase~!" Kisuke then clapped his hands twice, "Thank you very much for making this a worthwhile decision~!"
There were a few seconds of silence before the Deities who just left suddenly returned. They were shocked at the hostility that Shiva was releasing, but they immediately got out of the stupor and reported, "Indra/Shiva! The barrier surrounding the planet has been taken down and numerous ships of unknown origin were on their way down!"
Everyone turned to them, speechless and frozen. It was only after they heard Kisuke chuckling that they started moving again and returned their sights on them only to see him, still smiling, but this time, filled with gleeful malice, "You want to play? Here you go~. Let the games begin~!"