Mylune

Mylune is a forest nymph located at the Grove of Aessina in Mount Hyjal, and is later found as a champion in the Dreamgrove.

Cataclysm
The forest nymph has love for the wilds and wants to make sure everything is deemed safe from danger.

During the Firelands Invasion, she asks the adventure to continue the rescue to preserve the wilds from Ragnaros' minions.

Warlords of Draenor
Mylune visited the Lunarfall and Frostwall garrisons on the alternate and asked the commanders to rescue peachicks hatchlings from the Everbloom.

Legion
When Lea Stonepaw and the druid adventurer arrived at Ursoc's Lair, Ursoc himself was being attacked by the Nightmare sent by the Nightmare Lord himself. He called forth the wilds defenders to aid them with Mylune being one of them. She thought it was about the fuzzy little animals being in danger, but as soon as a creature of the nightmare appeared she knew something bad was happening.

To find G'Hanir, the Mother Tree and cleanse it from the nightmare, the druid adventurer asked the forest nymph surrounded by her animal friends for where to find it. Unfortunately she was in a state of depression and the druid adventurer quickly told her that there was hope for Azeroth to find the artifact. Mylune now confident since G'Hanir is really counting on them, they started to work by finding the Cup of Moonwater and let it be blessed by Leafbeard the Storied. Upon return, Mylune told her animal friends that the hero would fix this. As the druid adventurer started making their way to Tel'Andu Barrow Den where Naralex was waiting, Mylune told them to be careful because the Dream wasn't safe at this time.

Mylune alongside Naralex became the first champion under the Archdruid's banner. The Archdruid used Mylune's Flute to round up as many Teensy Weensy Fae Dragons as they could from the Nightmare. She was one of the chosen companions in Malorne's Nightmare sequence.

Battle for Azeroth
Claiming to have heard "the teeny tiny animals", Mylune arrived at Mechagon Island to aid the creatures by having the adventurer use sap from Nordrassil to speed the land's recovery. Upon completion of the task, Mylune informs the adventurer that she plans to report back to the druids of Nordrassil.

Cataclysm

 * Oh, Deer!
 * Save the Wee Animals

Firelands Invasion

 * Echoes of Nemesis
 * Nature's Blessing (quest)
 * Punting Season
 * Those Bears Up There

Warlords of Draenor

 * For the Birds
 * Put a Bird on It

Legion

 * Meet with Mylune
 * Necessary Preparations
 * Join the Dreamer
 * Teensy Weensies!
 * Champion: Mylune (quest)

Battle for Azeroth

 * Aid From Nordrassil

Cataclysm

 * Are there any teeny tiny animals in need of my aid?
 * 
 * I need to hug a bunny right now!

Warlords of Draenor

 * Hi! This fort is swell.

Legion

 * Oh, hi ! My woodland friends just couldn't stop talking about you after you left, and it was they who convinced me to come find you here! A noble with your courage and kindness just doesn't come along every day. This is going to be SO much fun, don't you think?


 * Greeting
 * Hi!
 * The little creatures need our help.
 * How can I help?
 * The trees need our aid.


 * Greeting (crying)
 * [Sob] Yes?
 * [Sob] Can I... help you?


 * Pissed
 * Do'h!
 * I'm not the dryad your looking for.
 * I need to hug a bunny. RIGHT NOW!


 * Farewell
 * Making trails.
 * I'm game.
 * See you later.
 * Take care.


 * Farewell (crying)
 * Bye. [Sob]

Combat ally

 * say
 * say
 * say

Battle for Azeroth

 * When I first heard the stories of Mechagon, I was worried it might be beyond saving.
 * When I first heard the stories of Mechagon, I was worried it might be beyond saving.


 * But, I can still feel nature here, underneath the rubble and wreckage.


 * We must restore it, so all the teeny tiny creatures can be safe!

Speculation
Mylune can be seen in Frostwall holding a bitten chicken drumstick which might hint she is not a vegetarian.