During the goddess abducting him a second time and him being able to speak common, something contacted tomoki and hibiki and gave them a secondary power. tomoki choose great offense, and the only thing he could think of was a nuke, he used it on the dragon killer, the way he described the effects and conditions he could use it heavily suggested nuke if not confirmed it. hibiki was contacted and she got a gift that allows her to become more powerful the more people believed in her, which if she is to become a moral authority then will be a great boon to her long term but doesn't have the immediate effect of a power boost like tomoki had, and while she was talking with that entity it seemed like they were not going to give makoto one, implying that he already had his.
at least the way I read it, and the visions he had, implied that this was a different life of his, where instead of finding emma first, he was first found by tomoki, became his friend, found the two later on, they died at the hands of the heros, and he decided fuck everything and and didn't hesitate to end everyone who opposed him. one of the things I remember was mention of 'maybe if we had another in their group' implying a male influence/friendship and not just the 2 girls, maybe things could have changed.
Its been a few years since I read it myself, possibly a translation issue or a plot point that the author decided goes nowhere, I dont know, at least that's how I read it.