Boutique constellation series pen cover _ How to use boutique constellation series pen cover?

There is a novel 12, which tells the love story of men in different constellations. What's the topic?

12 constellation series:

Aries Princess's Magic Hunting Plan _ _ _ _ _ Aries

Rainbow angel's love formula _ _ _ _ _ Taurus

God played you with a heart of stone _ _ _ _ _ Gemini

"The Witch Corps of the Demon Family" _ _ Cancer

The angel's super prank _ _ _ _ Virgo

Cupid's Challenge Law _ _ _ _ _ Libra

Angel Training Camp _ _ _ _ _ Scorpio

10 1 devil shooter _ _ _ _ Sagittarius

Savage angel _ _ _ _ _ Capricorn's demon baby

The Perfect Age of Stupid Angels _ _ _ _ _ Aquarius

The angel of the devil _ _ _ _ _ Pisces

The hunting prince _ _ _ _ _ Leo