Tips to keep yuria alive for the fight : 1) summon londor pale shade too, so he have a chance to get the aggro instead of yuria (he doesn't need to survive the fight unlike yuria). 2) Use powerful healing miracles like bountyful sunlight, med heals, etc... and spem them to constantly heal yuria and pale. 3) since they don't run into your heals; you will have to stick next to the boss and hold your heals until they get in range, timing is important but you shouldn't get the aggro since yuria and pale are both very offensive. 4) Use a talisman with a strong poise bonus and tanking rings, since miracles boosts won't get you far in this case, and you also want to be able to safely endure any accidental aggro while casting. 5) use a decent armor set for the same reason (i did it with the thorn set, so don't feel obligated to go full havel) 6) anticipate the healings by casting them a bit too soon. Regen spell are the best so prioritse them above all spells (especially bountyful sounlight). 7) don't be afraid to land some hits too, but be wary to do it only when they don't need healing. 8) for the second phase, be very careful of his wombo combo. You safely dodge it by getting behind AND away from him, since he will most likely target your phantoms. Wait for the final blow to heal them, they should tank the entire combo if you did your job well until that point. 9) plan to use many ashen flasks. Regular estus aren't that much important here since you will spam healing spells and won't get the aggro often.