Hojo

A member of the Kingsglaive, ranked Decima (10th) within the elite unit that reported directly to the emperor. Though he is the lowest ranked of the Kingsglaive he is still an extremely dangerous individual and is referred to as a one man army - he is an extremely intelligent, conniving necromancer who commands an army of undead minions and has even performed various experiments in altering these monsters.
He was granted a place among the Kingsglaive due his unique ability to maintain control over undead he creates permanently without having to use additional spells. This ability allows him to flood a battlefield with huge numbers of undead, and any killed by his minions are then added to his collection.
Ruvain informs the party of this information, along with the fact that Hojo is a cruel and twisted individual: seeing everyone around him as inferior and only having value as subjects for his constant experimentation. Ruvain highly suspects that Hojo is the accomplice supplying the undead horde bolstering the forces of the Order of The End cult that has attacked the Feywild.