
How to Defeat Archdemon Mercedes?
Dispel Archdemon Mercede's Buffs
Control Minions (Optional)
Don't let Yellow Minion Steal Buffs
Save 1 Dispel Skill for After Yellow Minion and Purple Minion Use Their Skills
Remember Yellow Minion Cleanse and applies Immunity buff
Dispel Archdemon Mercedes's Buffs
Buff Control is the key to this fight. The longer you can keep Archdemon Mercedes without buffs, the better. This is because Archdemon Mercedes gain two things when she has a buff on herself:
Her Basic attack triggers a follow up teamwide attack with chance to decrease Defense
She gains Combat Readiness whenever she gets hit
By constantly dispelling her buffs, we can limit the amount of damage she does significantly.

Control Minions (Optional)
Yellow and Purple minions does a lot for Archdemon Mercedes and unfortunately we cannot kill them. What we can do is control them and make sure they do not take too many turns. There are two ways to control them:
Apply debuffs like stun, silence, etc.
Bring AOE damage and kill them
When they receive fatal damage, they will become stunned. So that is one way to just use AOE damage to damage them.
Don't let Yellow Minion Steal Buffs
Yellow minion's basic attack has chance to steal buffs from our team and apply it to Archdemon Mercedes.
We can counter this by not applying too many buffs on our team or only applying buffs when we know we can dispel it or when Yellow minion is about to cast.

Save 1 Dispel Skill for After Yellow Minion and Purple Minion Use Their Skills
Since both Yellow and Purple minion's skills buffs Archdemon Mercedes, try to save one dispel buff skill after they use their skills.
Recommended Heroes
Some heroes we recommend for this Hall of Trials Boss. This list will not contain all the heroes so keep your creative juice flowing even if you do not have these heroes.
Healers/Cleanser
Heroes that can Heal and cleanse with attack skills is highly valued.
Roana

All the extra attack is good and heals the team
Revive buff cannot be stolen
Tamarinne

Buff Strip after transformation
Combat Readiness Push, Attack Buff and Dual Attack
Damage Dealers + Buff Strippers
Iseria

High Percentage Buff Strip and Defense Breaks
Unbuffable debuff
CD Resets works well with many heroes
Charles

Buff Strip
Great Damage
Lots of 'Correct the Posture' opportunities
Falconer Kluri

High Percentage Buff Strip
Sample Team Compositions
Iseria + Tamarinne + Damage Dealer + Damage Dealer
Falconer Kluri + Healer + Damage Dealer + Damage Dealer
Adventurer Ras + Buff Stripper + Damage Dealer + Damage Dealer
The main point is to keep Buffs off Archdemon Mercedes and the fight will be significantly easier.
This concludes our Hall of Trials Archdemon Mercedes Guide. See all our other guides here
Sez Gaming makes Epic Seven so EZ! Until next time!