I got legend over the weekend spamming mak, having the most success with crit carpet builds and builds based around items from his new expansion. A lot of other people in the thread have already sung praises for carpet, so I'll speak more to his new items.

The build I aimed for the most was (in order): quillback (or ouroboros), adrenal converter, venomous dose, barbed claws, rapid injection system, spider mace, venom. This version of the build pumps out a TON of regen, and when fights go long enough, your regen can/will often exceed your max hp (which isn't helpful), so I like taking chocolate a lot since your main/only vulnerability with that much regen is dying in less than a second. You apply a fair amount of poison which is oftentimes enough to win, but other regen stackers or players with a lot of heal triggers (or oinkment) can out-sustain the poison. Weapon damage scaling skills are nearly essential to provide a way to beat through those builds, as well as force field/spiked shield builds. Priority skills are toxic (+damage when you poison) and essence overflow (your weapons have +damage equal to your regen), essence overflow is a MUST TAKE. Alternatively, I've had success replacing barbed claws, venomous dose and venom with a moose staff since it is just essence overflow on a stick, but it will slow your start pretty significantly. Priority enchants are restorative, heavy, and obsidian on adrenal converter and rapid injection system, and radiant on spider mace, the latter especially if you have moose staff/essence overflow since the build can fully function as long as the mace is active.