5th horse girl: Dream Journey or Durandal? They're all ikze horses after all...
Knight's visor indicates Durandal. Dream Journey usually gets drawn as a lookalike to Orfevre (with similar bridle + rein headgear) but with darker hair and sans mask.
Funnily enough, there's already a mob version of Durandal in game. Paladin Sword, or as the Japanese fanbase calls her... Durandal, Mass Production Version.