I just started building with him but it's incredible how good AND flexible he is. He seems to combine early game push, action advantage and mid-late game powerhouse capabilities.

Powerful when you build around him and differently powerful when you don't include any support and just slot him in as dedicated defender with a moderate use of his ability.

Which by the way is crazy even without resource acceleration or dedicated attachemnets to pump it's attack power.

In turn 1 for 1 resources he defend AND attack back for an equivalent 5.

If you just consider that to achieve with allies an aggregate actions attack of 5 will take you likely 5 resources and 5 turns in tactic (considering only 1 tactic hero) and more than that in other spheres, then you soon realize you are not really hitting your board state using his ability.

Turn 5 is definetely quite a long way into most quests.

This weekend I put him in a deck with Mablung and I was able to use him almost every turn without giving up playing attachemnets or allies.

A single attachement (rainment of war) is enough to make him an elite attacked and defender. If you make a different use of his 2 restricted slot or add in capitain of gondor then the situation is even better although it will take more cards, resoirces and deck space.

I have not find yet an hero combination where he cannot fit in but racial decks or secrecy. Insanely strong.

In your experience how do you prefer to build with him?

Yup, he's amazing. I was building an Eagle deck and had Mablung and Hirgon all settled on, as playing Eagles is far less oppressive when you get an extra resource every round AND discount their cost by 1.

The third hero I went with Aragorn for the 4 attack out of the gate, but eventually switched to Grimbeorn and man... what a difference. The ability to defend and then attack for 5 on turn 1 is insane. Add Support of the Eagles on this guy and... whoa.