Blood on the walls

Ill mind of Hopsin 8, the lyric goes I can clearly see the blood on the walls. It's not a literal meaning, there's no blood.

Things done in secret that can hurt people you say you care about.

I took away every chance you had to make it big while telling you that I'm working for you to help you make it big. You didn't know about it at first but now you can see the blood on the walls