Ruka is a young girl who serves under Sonoka. She has a sadistic personality and has the power to control water and wind, however she states her specialty is electricity. In the English version of the anime, her name is rendered as "Luca".   (Source: Wiki)

After a lifetime of seeing ghosts, young Sumire is recruited by powerful Lucia to fight demons! The girls battle darkness as members of the Venus Vanguard, a group dedicated to ridding the world of its greatest threat—Virus. As they discover why every life is worth saving, they also learn their own unlocked potential for evil. (Source: Crunchyroll)

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Yui Itsuki is a Japanese voice actress who works for Holy Peak. As a musician, she is currently the lead vocalist for the band Yousei Teikoku (under the persona of "Dictator for Life" 終身独裁官, the supreme leader of The Fairy Empire).

"Welcome to Venus Vangard. We've been expecting you." 
Sumire Takahana is a seemingly normal school girl cursed with the ability to see malevolent ghosts known as "Viruses." Her life hits a crossroads after a run-in with a "gothic lolita" clad monster killer for hire, Lucia Nahashia. Not content to stay on the sidelines while these "Viruses" prey on the weak, Sumire decides to join forces with the mysterious eyepatch-wearing Lucia to hunt down these "Viruses" before they can hurt anyone else.
 
(Source: Seven Seas Entertainment)