Hyacinth was one of the major antagonists in Fire Emblem: Engage, and he was in a love to hate him kind of way.

He’s the only monarch of a kingdom that wants to bring Sombron back from imprisonment. And I’m assuming his dark magic is kind of a gift from his evil benefactor.

But even his children have second thoughts about his plan.

But after he kills a good king, you get a chance to enact revenge against him.

I didn’t find him particularly difficult to get out of the way, though your character doesn’t officially slay him.

As it is Sombron the evil dragon that devours him as a sacrifice. That’s some real irony there.