I have dark brown hair with a sorta red undertone..do i have to bleach my hair to dye it demi perman

If you want reddish color hair then you don't really need to. It won't be too obvious though. I dyed my hair using demicolor a month ago, and it's still a little red. I have really dark hair (though not exactly black),

You can refresh the color now and then by mixing a package of unsweetened kool-aid with conditioner and leave it in your hair for 30 min. every week.