This event is a collaboration between "Kantai Collection" and "Aoki Hagane no Arpeggio: Ars Nova". It has smaller scale compared to previous events, and the event takes place from December 24th, 2013 to January 8, 2014. With the exception of I-401 (original Kancolle's I-401 from E-3, not Iona/Arpeggio's I-401), the Fog Ships are event-only ships, which will be removed when the event ends.