This is an Expert Rift Event, opened by use of a Lure: Storm Legion Elite.
The Storm Legion Raincaller and Storm Legion Galebreaker will be spread out throughout the rift area. The best way to handle this is for the party to roam around the outside of the rift until they find a position where they can safely pull one to two of the mobs at a time. Both of the mobs can cast spells so be prepared to silence or line of sight them into moving out of the rift to the group. As long as the group avoids aggro'ing too many at once this is an easy phase.
This phase is very similar to the first phase with an addition of the Bound Screecher. There will be three separate groups set up in a triangle formation around the rift. Each group will have one of each type of mob in it. Simply pull them one group at a time and have the tank maintain aggro on all three mobs and this phase will go smoothly.
Artaer is an elite bird with 207k health. This fight has two main phases. The first phase will be an easy tank and spank where the group fight Artaer. When he drops belore 10% health he will summon three Galebreaker Elite that will begin channeling a spell at him. This will heal him. The group must move around the rift and slay all three of the Galebreakers. After they are dead Artaer will become vulnerable again and he must be slain for good.
The four minute timer may seem like a long time but if your group is low on dps it could become an issue. Each Galebreaker has 47k health plus the two times you must kill Artaer at 207k gives a grand total of 555k damage that must be done in those four minutes.
Throughout this phase packs of Flesh Ripper will spawn. They only have 11k health and are quickly dispatched. Periodically two Wild Storm will spawn and the tank will want to pick them up immediately. Have all dps switch to these and burn them quickly before returning to the Rippers. This round should take far less time than the 4:30 the group is allowed.
This phase starts out seemingly simple by grows in difficulty quickly. When Adain becomes active he will be alone. The group should dps him but make sure not to use any long term cool downs. When Adain drops to around 75% health he will summon three Wild Storm. At 50% he will summon three more. And at 25% he will summon Skyterror Griffon. The group should change targets immediately to the adds as they spawn and avoid doing extra damage to Adain until all (or most) of the adds are dead.
If the group finds themselves facing Adain, six Wild Storms, and the Skyterror Griffon, things can go badly fast.
This is simply known loot, it is not a full list of everything that can drop from this encounter.