this quest is some quite tricky, Inarius is easy to take if you have damage enough, and it takes a bit long if you have low damage
the hard part is, prevent Lilith from the frozen orbs, just simply step on the orbs nearby Lilith when they stopped on the ground, and it must be your priority work, and it is the key to victory.
also lure Lilith away from Inarius, get in-range of Lilith so she can cast Blood Ritual for you
try again and good luck