This is a Final Fantasy Record Keeper (FFRK) event. This is a Final Fantasy VII (FF7) event in which focuses to the story of Vincent Valentine. In this event, you can recruit Vincent, Zack, Yuffie and Reno and you can also get their memory crystals . You can get he Memory Crystal II (MCII) for Vincent, Zack and Reno.
You can get these abilities in the event:
↪lowers all enemies’ Attack, Magic, Defense and Resistance.