Primal Dungeoneer is definitely one of the strongest cards of the Wailing Caverns mini set, and Zeh tries to integrate it to the already existing Aggro Doomhammer shell that people have been trying out in the last few months with not much success.

While Wailing Vapor acts as a solid game opener with potential to deliver some relevant chip damage, Selfless Sidekick allows you to equip Doomhammer without having to pay its Overload cost, especially in case your Custodians don't want to show up.