If you have Timerion with Equalizer it's ez pez.
Your team could be :
- one speedster/denyer (Thetys, Caillech, Frostbite...)
- One hard solo hitter (Barbatos, Voltaik, Shalinnar...)
First turn, freeze every one, or Stamina drain if you play Thethys
Then Timerion's turn, just go Equalizer on the 300k pv Uriel, so that he has only around 24k pv left
Then with your hitter just kill the 24K, and you're done ! The 2 other uriel shouldn't play for one turn, wich means you have 1 other free turn to kill them.
I just did it without even being touched that way :)
But then again, the key is to have TImerion/Equalizer, otherwise.. Good luck ^^'