Early-mid game player need guide.

Hey guys.

I am kind of early - mid game player. Now I can:

Do every fusion easily.

20 all dungeon (hard 10 dragon, all others haven't try yet since they are much harder and their set is not that good anyway, except FK)

2 keys UMN (still waiting for doompriest to give my helicath unkillable team an extra dps slot)

hydra normal and hard 1 key.

chimera normal and hard 1 key.

Clear most of grim forest hard, but can't beat a few boss.

Doomtower normal: done. Hard: stuck on that fking bug.

Sand devil: waiting for godseeker. Shugon: Haven't tried it yet.

Arbiter done. Marius stuck on sand devil.

SO.............
I am a pvp enjoyer and like RTA (thank to predator who give me a chance when I face old / whale account). And I realize that gear is the issue for me mostly.

So, to improve my account, should I focus on hydra champions (provoke & aoe block buff) or grim forest champs? I feel like mercurial is more powerful right now, but also stoneskin + ignore def set are kind of important too. With limited resource I want to know the priority!

Any insight would be greatly appreciated!