Mercia can be a pretty good counter for Rhea Glad. She can almost recover most of the damage dealt by rhea granted she does not get stunned on first strike.Rangers and Gaurdians have different roles. Rangers are designed to deal damage not withstand blows. i can win against rangers too but not without a casualty they either hurt my units badly or take out 1 or 2 of my units. ranger are damage dealers! they Excell in damage dealing and triggering department and because of you have to set up your squad in a certain wat and need to have a certain unit to counter their endless trigger. You don’t even need to counter mercia she isn’t even a threat. AI usually ignores Gaurdians and focus on squishy units so Gaurdians is mostly useful for their protection aura.If we are simply talking about ranks, currently I am rank 29 in arathos server and above 4.3k. I fight the top and most fed squads in PvP. Mercia CK appeared in top 20 for a short while but Guan Yu was released so yeah. I also know from experience that a fed cass, guan yu and rhea are a nightmare to deal with especially since I am using a defensively-inclined squad.
I am from Gevalon Server. Current at top 300 Crystal 3 Rank. The Top 20 here are mostly use Cassandra, Rhea, Arthur, Guan Yu, ZL warlock and Snow white and lastly trigger hex and archer squads.
I’ve encounter Mercia CK once and she was not a problem to me. More people are actually using Guan Yu paladin now because her active skill and aura is insanly good and synergize well with Rhea and archers.
By using your same argument, can I say that rangers are garbage because I almost never lose to them? Doesn't mean that you have no issues facing that particular hero is tantamount to them being useless. You most likely just have the tools to deal with her effectively and guardian AI is wonky tbh.
In short:
I beat ranger because i have to set my squad to counter them, i beat mercia without even a counter unit or counter squad for her. So there, the context of argument
Gaurdians are designed to take punishment but since AI would prefer to pick off weaker units them tanking isn’t really a main role anymore. Gaurdians are only useful if they have a really good protective or retaliatory aura. Return damage, absorb damage and damage reduction aura for me are the most useful aura for a Gaurdians.
Mercia would have been really good if her aura was
Like 100% to return 40% damage when adjacent ally is hit. Return damage is a death sentence to Rangers and Shadows. Shadow like cass and aladin would be kill them self with return damage especially if they Crit.
Mercia bk has heal and increase mag but there are other attainable Gaurdians that has similar aura. Yeah Mercia BK has a good active skill but i rather have snow white AB for her slot or a guan Yu pl.
Mercia CK also has a good active skill useful for breaking formations or taking the mid tile but her aura is just mediocre stat boost aura are one of the worst auras in my opinion.
She is good depending on your strategy, to me she is plain bad. Her are my other reasons
1. Her aura BK or CK is not that special there are other attainable gaurdians with the same aura. Leon, Victoria and Faye.
2.Her skill maybe good but I didn’t play PVP to take the center tile. I play pvp to kill every opponent. Hence I’ll have my tanks protect Rhea from an Archer onehit kill. Arthur PL + Guan Yu can effectively buffer off 70% incoming damage from rhea. Mercia BK has heal but Heal isn’t effective in the Arena unless she has 20k hp but even that still only heal 2000 HP and that’s it counting arena’s reduce heal. Def doesn’t scale well against ATK and CRIT so i would definitely go Auras that has damage reduction or damage absorb.
3. She is hard to limit break unlike Leon, Victoria and Faye. unless you are really luck with the gem summons and were able to pull mercia consistently. Although not necessary limit breaking your hero will still give you an edge in PVP
Everglades has the same prevailing arena meta as you mentioned, GY, Rhea Glad, Cass sin, etc., As a non-dark lord user, I had been struggling in climbing back in arena rank for quite some time after Cass came out. When Mercia was released, I was instantly smitten with the BK and I am now able to compete at the top level of arena against all the Cass, Rhea, GY combo.
But of course, the strength of your squad does not depend on the strength of each characters, but how you combine them to come up with the strongest possible comp to combat variety of meta.