The following is Open Game Content from a 3PP Source
Aura strong abjuration; CL 15th
Slot armor; Price 53,650 gp; Weight 55 lbs.
Oni armor consists of a suit of +2 do-maru samurai armor and includes a kabuto with menpo. The menpo has been constructed in the stylized guise of a fearsome oni. Like the armor’s namesake, the wearer of the armor is resistant to spells, and is graced with spell resistance 13. In addition, once per day the wearer can direct a cone of cold spell at his enemies, dealing 10d6 points of cold damage (DC 18 Reflex ½). While wearing a suit of oni armor the wearer is treated as having the Exotic Weapon Proficiency (kanabo) feat. The wearer loses the benefit of the feat if the armor is removed.
Requirements Craft Magic Arms and Armor, cone of cold,spell resistance; Cost 27,150 gp