To me it sounds like there might be more than just a single Warrior of Darkness since the voice says "it's time for you and your's to join the fray... Warrior of Darkness". Almost like the Warrior of Darkness is bringing his own party. This got me thinking that we may be gearing up for an Ark Angels/Divine Might style fight which has me hyped.

It'd even further fit since that fight was in the "sky" expansion of FFXI and this is the "sky" expansion of FFXIV.