Baal, the Emperor of Monsters, was created by the evil energies at the beginning of the world. When Nature created the world, it knew that the people needed the good and the evil energies to stay in balance. Because it's something natural. When you assume something is good, you're automatically admitting there's evil.
Baal is not a beastman, he's the pure evil in body. He created Monster Kings to keep the evil energy living in that world, but of course, he got too used to being the strongest energy for hundreds and hundreds of years. And, now, Astri is different from all the others before her, and he's sensing the usual control he had, which he doesn't have anymore.
"Are you jealous? I didn't know you had a thing for Kangki. Sorry, he's my male now, and I won't let you take him from me and my family. Besides, if you try to consume him again, he won't turn into a Monster anymore. He accepted me entirely and by free will." Astri says.