I couldn't miss the chance to practice my drawing!
Bestow defense up/magic defense up.
Shining Ruby is a Blood Pact: Ward ability for the Carbuncle (level 24). It increases Defense by 10% and reduces magic damage by -4% for 3 minutes. It costs 44 MP to cast.
Shining Ruby is an active ability that bestows Defense ↑ and Magic Defense ↑ on all targets for 4 AP. It can be used by Carbuncle.