Leviathan's Love for a Tailor's Heart

Hades, a devildom renowned for the beautiful silver-grey walls of its palace nestled in the mountainous terrain, unfolds its tale in the 18th century.
The palace stands within walking distance of Lavender Town, a quaint human village, and a dense forested area. Ruled by the legendary-grade devil King Leviathan, the palace is adorned with loyal subordinates: Foras, Barbatos, and Glasyalabolas, all special-grade devils.
Their unwavering loyalty is so profound that they are willing to sacrifice their lives if King Leviathan were to perish.

One fateful night, a legendary-grade devil infiltrated Hades with the intention of killing King Leviathan to usurp his throne.
Using his hypnotic abilities, he seized control of all the devils in the palace, leaving Leviathan unaffected. Faced with the dilemma of not wanting his devils to suffer, Leviathan surrendered and was beheaded.
His body was discarded into the human village but he miraculously alive. But, where did his head go?

He encountered Harumi, a skilled tailor who generously offered her home for him to stay and help him to find his head, so he could create a revenge strategy in proper body. In return, she wished for exceptionally expensive fabric from Hades.
As partners in crime, they embarked on a perilous journey together and amidst the chaos. Romantic feelings began to form from one of them.

Peace arrives, the question arises: Why did the evil force want to kill the ruler of Hades? Will they be together at the end of mission or separate ways? Will one of them be possessed, if yes? Which one of them? Is there a love triangle? The tale unfolds, revealing the destiny of these unlikely allies and bigger challenges to come.

*I have wattpad too, @/ dreamLand45
Character of story is from "What In Hell is Bad" game.
Cover page- https://pin.it/3NshkOT