mia_(halloween)_(fire_emblem)
Tag used for Mia (Fire Emblem) from Fire Emblem specifically when dressed in her Halloween/"Harvest Festival" attire from the Fire Emblem Heroes 2018 The Land's Bounty banner.
Note that it's possible (especially for older artwork) to depict Mia in a Halloween-themed costume without it being the one described above, in which case this tag should not be used.
TBU