Danny “Brick” Brickwell
Brick is a bulldozer of a Green Arrow villain, but he also has the brain to match the brawn, and that makes him more dangerous. While Arrow’s Brick deviates a lot from its red-skinned comic book counterpart, there are plenty of similarities: Brick does elevate his role of a low level enforcer to a boss, and he does have an interest in the Glades in the comics.
He’s also able to shake off a gunshot to the head, but his aforementioned brain is what makes him particularly tough. I don’t think Brick has taken Mirakuru; he’s too in control. In the comics, Brick is a metahuman, and I think that’s the implication. We may have another Arrow villain with ties to The Flash.
He’s got a Demon Head
Malcolm Merlyn refers to Ra’s al Ghul by one of his many monikers, “The Demon’s Head.” This is actually a variation on the Arabic translation of Ra’s al Ghul’s name.