It seems players that don't already own the abysea expansion can only use it if for the length of the campaign, and players can only have a huge increase in traverse stones during the event... it seems that the cruor given and the lunar abbysite we get to keep, and I am hoping we get all the atma's and get to keep it them all but for the sounds of "participants" it sounds like that is only the case if you try the event, which should be no problem...