Ruri "The Second Lapis Lazuline, Blue Comet, the Blue Magical Girl" Yoneda
About
She is part of Team Bell and the only one who understands Melville's speech.
Her magic is to teleport using gems.
She is actually the Second Lapis Lazuline and her previous name is Blue Comet.
(Source: Mahou Shoujo Ikusei Keikaku Wikia)