Depending on where you face ML Mercedes, be it stage 10-10, Hall of Trials, or in RTA, most of her damage comes from residually chipping away at your team. This coupled with debuffs such as Burns and Blinds, and paired along with the Artifact Fairy Tail of a Nightmare will result in even more chip damage, makes her a real threat in extended fights. Good Heroes for this role include:
Emilia Ray Elena
Other Ways To Beat Archdemon Mercedes
Here are a few other Heroes who will help you take down Archdemon Mercedes and Archdemon’s Shadow.
Alternate #1: Roana
Roana is great for dealing with Archdemon Shadow’s extra attacks. Archdemon Shadow has a chance to proc an AOE whenever she uses her first skill. Additionally, most Archdemon Shadows in RTA are built on a counter set. Roana will heal and push the team forward whenever Archdemon Shadow activates this ability.
Alternate #2: Little Queen Charlotte
You won’t have to deal with Archdemon’s Shadow if you simply one-shot her. There are a number of dedicated powerhouses capable of pulling this off. The most obvious choice would be Little Queen Charlotte on a Penetration Set. Most Archdemon’s Shadows are built relatively tanky, and you will need enough power to break through these defenses. Alternatively, a strong enough Hwayoung may also be able to get the job done, depending on her stats.
Alternate #3: Tamarinne
Tamarinne is excellent specifically for defeating Archdemon Mercedes in PVE, whether it be Adventure Mode or the Hall of Trials. She can strip buffs, AOE cleanse the team, buff Attack – and when paired with Iseria, she can do all of this on a very low cooldown. Tamarinne is great in every PVE mode, but she works amazingly in Hall of Trials, in particular for being able to dispel any buffs that get stolen.