Kuja is visibly repulsed by the 'ornament'. "Good gods, what is that-" He clears his throat. "Ahem. Hello again, Klo'oa. It's certainly been an... enlightening experience."
He gestures to the Eidolons depicted. "I'm not certain how it works here on Vaikuntha, though I expect it's all handled through Asterisks. On Gaia, Eidolons are powerful spirits that can be called from the Aether and commanded to perform certain tasks. There's a rather complicated ritual that involves a crystal or precious stone, attuned to the Eidolon's spirit. Sacrifice the crystal and offer a gift of magical potential, and the Eidolon will appear. Once summoned, you'll have an extraordinarily powerful servant for as long as you can sustain the beast's physical form. Anyone can do it with the right magical know-how and enough mana, but of course Summoners have a particular and uncanny knack for it."