User blog comment:Seieireppa/Crimson Orochi defeated... again/@comment-24459992-20150622152008/@comment-26157862-20150623032752

I think the weapon the NPC gets after you clear it is the same as the one you have equipped during the mission. So if you want them to use a Long blade, you have to equip a Long blade during the mission. At least, that's what they say. ^^