For anybody having trouble with Dark Fae floors.
Just wanted to share my strategy and general idea of my team builds in case anybody is having trouble... You dont need the champions I have but I have cleared 120 a cpl times using this exact same team and builds.
She is slow, and her Dopplegangers have mirrored stats to your Champions, but you should always get to take the first turn. I'm not sure what the speeds are, I believe they have Dark faes speed which isnt that fast. You want a speed booster/TM increase as your fastest champ, mine is high khatun @ 225 speed. Then another AoE enemy Speed decrease champ over 200 speed. I use Psylar who is Godtier at this.
Once you have them take their turn,. your whole team should be able to take a full turn. you want a nuker as strong as you can get, high Attack/Crits, As little HP and DEF as possible but able to survive first two rounds. I use 3 lvl. 60s, Chonoru (ATK) (4000 ATK 125 Crit DMG) and Sicia Flametongue ( High ACC to ensure the extra Turn after A3) (5000 ATK 150 Crit DMG & 250 ACC) then Kael (roughly 3000 ATK, 70% Crit rate & 115 Crit DMG) None of these champs have more than 30K HP and 2000 DEF in their build. I was clearing these stages long ago before I had Sicia or Chonoru at lvl 60, and still had success.
As you can see, I was only attacked once, and barely took any damage. On harder floors it does take many more turns than this. High Khatun is Godtier for this because of AoE Ally speed and TM inc. Plus the A3 which with a good amt of ACC can decrease enemy TM. when it comes back around for your second turn.
another good strat. is to use a champ with HP Ally shield set on, very little DEF,then have a Buff stripper really fast take a turn on them. As far as I can tell, Special Accessories like Cleansing and Revenge, or Reaction accessories arent reproduced on enemy team. Im not sure about masteries but I do have Counterattack and defensive (Defense column) masteries for a cpl champs. I have full masteries for Kael, Sicia, HK and Chonoru. Helmsmasher is probably the best option for your Nukers in this build as Dark Fae starts aquiring some pretty high DEF numbers in the later stages. ( Cant see boss stats, but, a year ago we used to be able to see the total stats of the enemies in each DT floor, Wish that was still a thing)