What If the Strongest Final Boss from the Original Story Became the Protagonist's Ally?

“Yu, it’s become Eugram!?” original fantasy novel 『 holy hero Iris 』 made into a game. One day, the man was reincarnated as the strongest final boss, Eugram, the villainous character that appears in that work!? Although he achieved his long-awaited reincarnation into another world, there was no way he would be happy to be reincarnated into a being burdened with the fate of death... When he came up with the idea of exile to avoid a tragic future, he headed to the kingdom where the main character, the enemy princess Iris, was. Our goal is to live a leisurely and luxurious kingdom ☆, and when an encounter that was not in the plot is fulfilled, the fate of the two begins to change in a new direction! The most powerful final boss who defected to an enemy country and the neat and pretty (slightly cerebral) protagonist's flirting and cheat exile life begin!!