Yes, there is a manga for Takt Op Destiny. It offers another way to immerse oneself in the world and adventures of the series. The art style might differ from what you expect, but it still brings the story to life.
Anna is another important character. She plays a role in guiding and supporting the other characters. Her knowledge and skills contribute to the group's overall efforts in the fight against the D2, and her interactions with Takt and Cosette add depth to the story.
The story of 'takt op game' is set in a world where music has the power to fight against the D2s, which are creatures that hate music. The main character, Takt, is a Conductor who forms a partnership with Musicart, like Destiny. Together, they embark on a journey to save the world through the power of music.
Well, it could be. But often, even if inspired by real life, there are likely embellishments or alterations made for narrative purposes. You'd need to look into the author's notes or research about it to be sure.