Basically the event quest wants you to defeat a boss then defend it.
White dot is where the boss needed to be protected will be at, the 4 red dot is where the monster will be spawning and the arrow indicate their movement. Yellow dot is where the Ghasts will be spawning and the yellow arrow is the movement for the Ghasts, Blue circle is the area Blinkers will spawn and the Pink circle is where the Bisque Dolls will be at.
The mission's monster are all pretty weak to high level players so it is actually quite easy if you can 1/2 shot the monsters. Is not that newbie friendly though, which is why you might want to use those Smile Pumpkin to possess the bisque dolls. There's couple reason to do it:
1. Some dolls have pretty broken setups, like archer have 2 set of arrow revolver skill with final shot (use one then switch to the other), Fighter bisque doll can access Chain 2, 3 skills without chains at all (still have cooldown) etc...
2. The dolls have pretty decent stats, knight dolls can 1 hit smash the blinkers, hail doll have 2xxx mp that will never run out of hp, and all the dolls have 2xxx hp which is good to tank on the explosion monster later on.
That being said though, some dolls aren't great for the mission, but of course if you are a weaker char you might as well become a doll to save your equip's dura and what not.
The key points to success is actually very simple... output damage... but there are few points that will make it easier
-If you are melee... don't chase the monsters... you will never catch up... the monsters have stop points, wait there, set up windmill.
-Blinker, Ghost, Ghast are priority over the other monsters, because blinker's drain hp will really dmg the Boss and Ghosts will receive only 1 dmg from magics, likewise Ghasts(They are nerfed-version) have respective PD.
-Ideally setup 4 person to each gate and 2 person(stronger players) will guard the center.
-Boss can be healed, if you have a mage/healer in party have them heal during the idle periods.
-Wear explosion defense gears to reduce dmg from explosion enemies.
In the end it still boil down to protect the center and deal as much dmg as possible to protect the boss.
Rewards... yea they are pretty much all the shadow mission drops item from various shadow missions (including like market upgrade coupon), with the addition of some special potions and things like dyes and what not...
Collecting 10 incomplete commerce reforge and you can restore it to a commerce reforge kit, which "can" give the special effect movement speed increase during commerce. For normal equipments, the highest level will be level 10 (at r1 reforge), but when used on G15 NPC items it can get up to level 20.
I guess that's all.