I did not think I'd add this role, but I think this would be a very fine addition. So this role is for our main character. Well, their ghost. So story-wise, our MC died of the plague three years back, but one of our LIs, Asra brought them back to life by making a deal with the Devil. This ghost is nothing but the guilt in the hearts of the LIs since they couldn't save the MC on time. Yes, MC did resurrect, but the fact that the MC had to bear so much before the passed, caused immense guilt within the hearts of the LIs. This ghost is a representation of that. 

Voice wise, I think their voice would be hollow. Imagine a trapped spirit, exhausted, filled with spite. They want to scream and rage, but they're tied to the mortal world because of all the guilt. They don't have a clear voice, just a hollow cry. Yeah I went a little too poetic there, I'll leave the rest to you talented bunch.