4e Warden for Pathfinder?

[Cubic Prism]

So, I'm looking to create a antagonist for my campaign, and would like to base it off 4e's Warden class. The hard as a rock, nature transforming, difficult terrain tank. Thoughts on how to pull this off as closely to the abilities the 4e version has?

I've seen thoughts on making it based off of a Barbarian, and Druid. While those classes certainly share some of the traits the Warden has, I'm unsure how to really build it out and not feel like I'm missing something. As this is a likely antagonist for my players, I'm open to building it via classes, templates on existing monsters, class levels on monsters etc.

Thanks for your time.

[Kazumetsa Raijin]

Druid + Skald perhaps.

[Mechagamera]

I like the 4e warden too. On a mechanical level, the warden's abilities are primarily to get a combined buff plus enhanced melee attack a certain number of times a day. That sounds barbarian-y to me. Ditto the "Jekyll and Hyde" style alchemist with a little refluffing. I am not familiar enough with the bloodrager to know if that would be a good alternative or not.