Playing the role of the pitiful figure, he would attack the city lord mansion, something that would likely end in failure. Even with his vajra body, though he could severely suppress even Immortal Gods and those below that rank were nothing but ants as long as it was active, it still wasn't quite enough for him to face up against such an existence.
After he was on the verge of losing his life, the rest of his plan would kick into motion. His clones within the other three factions would make their move. Using their friendship as the four geniuses of this generation, they would use the support they gained to launch an assault on the mansion as well.
With the devils attacking the city, the various factions were uniquely vulnerable to internal strife at the moment, so the plan would have likely reached this step without a hitch.