Miku is another one of the main characters and the deuteragonist in Symphogear and is the wielder of the relic known as Shénshòujìng in Symphogear XDU. Miku is a helpful and cheery person in her everyday life, always wanting what's best for her friends and allies, Especially Hibiki, even if she teases her every now and then. For Miku, Hibiki's well-being takes top priority, doing everything she can to support her and give her the encouragement she needs, to the point where it's borderline possessive (Albeit, she keeps that possessive streak hidden from the others). But even while she does what she can for Hibiki's well-being, Miku knows that Hibiki's desire to help others will always be there, so when she can't be with her, she does what she can to make sure Hibiki always can come home to the warmest place she knows: Her sunshine.

Miku's JP VA, Yuka Iguchi (Miku and Hibiki on a date)

For her English voice, I see her somewhere between Stephane Sheh's Histoire from Hyperdimension Neptunia (Histoire Example ) and Julie Kliewer's Florina from Fire Emblem Heroes (Florina Example)

However, I'm interested to see how you decide to interpret her voice.