Levels 11 & 12 have a regular Lilith.
Levels 13 & 14 have Dark Lilith and her passive: "Deal 500% of a random enemy’s MAX HP as true damage and heal all allies to full HP when an ally dies."
Orbit talis block True Damage.
Level 15 has Lucifer & Dark Lilith, they get Soul protect from one of the Onyx sons.
It can be expensive, lvl 15 is 35 SoT per battle.
Having all the relics and Orbit talis &/or the latest OP toons is suggested for levels 14 & 15.
Good Luck!