To max your grimoire you'll need all three characters. You'll need to get 30,000 PVE kills as a warlock, and 5,000 PVP kills as a warlock. That's 30 grimoire score you wouldn't get if you didn't make a warlock. If you're ok with that, then don't do it. I'm curious though... You had a warlock before and deleted it? It took longer to find all the accurate information than it took to write this post. I'd say it was a week of on and off research, and two hours to write the post. I just wanted a place where everyone could get accurate information on grimoire. I didn't want everyone else to have to spend a week to fully understand grimoire, but 15 minutes.