There is only one way to acquire it, and that's through its quest. You can opt to start it at 100 after dealing with the Broken Shore, Dalaran, and Peak of Serenity scenarios, or you can choose to start it at 102 as your second or third artifact for Monk.
There are two paths you can follow, depending if you prefer the functionality of Dancing Mists or the healing gain of Extended Healing.
If you're starting Mistweaver right out of the gates of Legion's launch, I recommend the Extended Healing path, as its path is better for 5 man content, the main content for gearing up in the early expansion. If you're spending points in it for raiding as an offspec, use the Dancing Mists path, as it has more benefit for raiding, once it opens.
Extended Healing Path:
Dancing Mists Path:
(Updated pictures made by tenisius)
Sheilun's Gift is a variable heal that is powered by mist clouds. One mist cloud spawns every 10 seconds in combat, stacking up to 12. When you cast the spell, all mist clouds are consumed, even ones that spawn midcast, and instantly heal the target.
The Mists of Sheilun is the first golden dragon trait we want to go for, as it increases Renewing Mist's healing considerably. It procs roughly once a minute, and its AoE heal rewards proper positioning once it ends.
Mists of Life causes Life Cocoon to apply our two HoTs to the recipient, which are then instantly buffed by 50% for as long as the shield lasts. This trait turns Life Cocoon into one of the better single target cooldown, as it can either save a party member's life, instead of lowering the damage they're taking.
Extended Healing could have been a flat 5%/10%/15% healing bonus to Renewing Mist, but it instead adds 0.5/1/1.5 ticks to Renewing Mist, which also adds on to each Renewing Mist having a higher chance to proc Uplifting Trance.
Dancing Mists causes Renewing Mist to sometimes duplicate itself at Renewing Mist's full duration on another target in your group. If you want to maximize your Renewing Mists, then you can cast it on either full health targets or those close to full health, in order to cause the most jumps a single ReM can do.
Blessing of Yu'lon causes each target healed by Revival to be healed for 30% of what they had been healed for over 6 seconds. This means if the Revival heal Crit on a target, they'd heal for 30% of the Crit, or 60% of a regular Revival heal. Haste, unfortunately, doesn't make it heal any faster or add any ticks.
Celestial Breath causes you to heal allies around you whenever you press Thunder Focus Tea. It's cooldown is always 30 seconds, so those running Rising Thunder aren't healing any more with this spell than those not running RT.
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