Hi Thrifty and welcome!
The Beast is just your basal urges and emotions, and your AV (Addictive Voice) is his/her mouthpiece or agent.
I don't use a persona for my addictive voice. Mine is just an omniscient sort of echo that I hear in the background and observe as noise. If you try to force it to go away, it just gets louder, so let it be. Let it talk all it wants. It doesn't matter to you. Eventually, it gives up, but it never goes away. Nor do you want it to. It's part of you, and it's normal.
Other posters here do personify their AV, and even their Beast. The Beast isn't "bad" per se, it just may want illogical things. Your addiction lives there, and so do things like your sex drive, your animalistic wants and needs that may or may not be valid.
I am not an AVRT spokesperson, so it would be better to get input from Terminally Unique, who runs this thread. Others may pipe in to give you some ideas. For example, one poster likes to think of her Beast as some horrid, disgusting, dirty fat pig, with rollers on and a cigarette hanging out the side of her mouth -- or something like that, ha!
Gather some thoughts on this. Read all the way through this thread, AND the thread that preceded it. There's lots of good thoughts on here!
And welcome! This is the way I quit over 20 years ago, and it is the way I live my life now. I love this thread. This concept is not new, and it was not "named" at the time when I quit, but the way it works is the same. This method is true self empowerment and validation of yourself as the strong, powerful person you really are. If you don't feel that way yet, you will.
Recovery with an attitude is how I look at it. I have attitude for sure, in lots of ways, and certainly in this way.
Much love, and much luck!
FT