The Avernic Defender is a top-end defender in game, as well as being a top-end melee offhand in game. It requires 70 Attack and Defence to wield. It has some incredible defensive bonuses, some solid melee accuracy bonuses, and a respectable +200 melee strength bonus.
Although it is quite powerful, the Avernic Defender does not see a lot of use. It is significantly rarer than the top-end melee offhand, the Inferno Spirit Shield, and is therefore hard to find and not much cheaper.