Permanent black hair-dye and bleach

After having light brown hair for a good five months, I want to go darker than my natural hair. I've been wanting to dye my hair black for a long while, even before dying it for the first time.

I'm most likely doing it at home, and this will be my first time doing so. Could I get away with not using bleach? I've also been doing research which includes watching videos and tutorials from licensed cosmetologists online.

Please let me know whether there'd be any difference between using it and not using it, and sorry in advance if this is a stupid question, I'm new to the hair-dye world!