From DivNull RPG
The term "reinforced breastplate" refers generically to a type of medium magical armor.
Juuken wears a black jade suit of this type of armor named "Necessity of the Guard". It is additionally enchanted to allow him to spend 1 mote to breathe underwater for an hour.
Summary: Medium magical armor
Materials: jade, orichalcum, moonsilver, soulsteel, starmetal