Key elements in beating this encounter (from a healers perspective) is to refresh the emerald vigor buff on every portal phase, and good use of cooldowns.

Here is a few tips that helped me to refresh the buff on every portal phase:

- Position yourself by one of the portals BEFORE it becomes active (before you can enter it)
- The second you click on the portal start flying up to the nearest orb (in order to refresh the buff)
- Once your time in the portal room is about to end, position yourself in front of Valithria (that way you use minimum time to run to the next portal, as Valithria always cast the portals in front of her)
- The Risen Archmages cast frostbolt volley, slowing your movement speed. Make sure to remove this slowing debuff from the healers as it may prevent them from refreshing the emerald vigor buff ( It is still possible though, even with the debuff).
- You should have 5-8 seconds to refresh the buff once you can enter the portal.

There is no point in skipping a portal. 20 seconds of 50 -100 k heals is far better than staying outside.