Against him solo he is easy IMHO. I just put out WuKong, Blizzar, and Mythrala. I could probably just defeat him with the first two. Mythrala has high enough base resistance to avoid being stunned in most cases. Even so I would think that a champion with block debuffs in an immunity set or stoneskin will give you what you need against a single Armanz. 

My 4th that I usually put out is Snick but you could also use someone like Drex or Toragi. 

@dthorne04 another Thorne is here 😆 

Bring one high resistance Cleanser and he's not a threat. If somehow you can't do that, avoid teams with him or get your speed higher on one champ to nullify him.

There's been several threads like this with the core argument of "Only one champ can do this to a whole team" and that's not a real argument. There's plenty of champions who, in certain roles, are unique. 

Look at Georgid the Breaker: AOE Nuke with unresistable TM decrease for any who don't die. Then his A3 (which ignores every buff) also grants a extra turn. Oh and his passive makes him ignore 50% of a target's armor, which means 100% if it procs with Helmsmasher and wearing Savage/Lethal.

How about Hedgmon? ALWAYS goes first and has a AOE skill lockout.

The point is, there's a lot of nonsense out there that can ruin your fight. 

Accept no imitations. 😠

Never imitated, never duplicated.

as we all know speed wins the race  in arena...get faster... but there are other debufs/buffs  you can use to counter = but at end of the day all comes down to speed