Tet

"When I saw you, Master, it went "Kira" and became "Kira"-ppy and was "Kira"-ness

About Tet
Tet is a mysterious guy who uses "Kira" language. So far, only his best friend, Edgar could understand it. Although, he has a cat's eyes, he does not has cat ears so he always wear a cat ear cloaked clothing. He is good at cooking but what kind of dish will be is for you to look forward to.

note: In Japanese, "Kira" means glittering; sparkling; glistening or twinkling.

About Gem
Translucent yellowish chatoyant chrysoberyl is called cymophane or cat's eye. Cymophane has its derivation also from the Greek words meaning 'wave' and 'appearance', in reference to the haziness that visually distorts what would normally be viewed as a well defined surface of a cabochon. Source