How can I say this in japanese?

I thought of "Oni wa watashi no naka ni aru" but it didn't sound good to me. Any other ways to say it?
I want to say "The monster lives/lies within me".

Oh, and by the way, can I say "tenshu no rap tsui ta?" just wanna say the king of rap music has arrived.

As you can guess I'm trying to write a couple of verses in Japanese for my songs hahah

thank you very much!

The word "oni" can mean "demon, monster," etc., but when Japanese people hear that word there is a particular kind of "ogre" that appears in old Japanese folk tales, which bring up a somewhat humorous picture, so if you really mean a scary monster, evil, demon, that is not really the word you'd want.

About the second one - where did you come up with "tenshu"? Also it would have to be "rap no (king)," the word order must be reversed. "tsuita" simply means "arrived," as if a parcel arrived, or a train arrived at a station. If you mean something more solemn like "descended (upon us)," you'd have to pick a different word.

Overall I'm just trying to say that it might not be the best of all ideas trying to write verses/lyrics in a language you don't know.