There are several choices you have under the category Halloween Fortnite Costumes, including Merry Marauder, Fortnite Raven, Omega Fortnite, Drift Costume, mikucosplay.com etc. Halloween Costume For Kids. Open registration will be on the Friday and Saturday of the convention at the Cosplay Table so long as there are spots available. You are NOT REQUIRED To have custom lighting cues, but any requests will be due no later than FRIDAY, (April 8th) – one week before the convention.