"Shiryou jutsushi nado kegarawashii" to shokei sareta node, mazoku ni tenshin itashimasu

A duke’s daughter and the crown prince’s fiancee… I, Rachel Sheringham, was both and wielded dark attribute magic, which allowed me to use necromancy. I was accused of colluding with demons due to it and was executed.
With regret as my source of power, I will return to life as a lich!!!