Magical Girl Lyrical Nanoha Vivid

[xstationo 0]

Written by Masaki Tsuzuki
Illustrated by Takuya Fujima
Published by Kadokawa Shoten
Magazine Comp Ace
Demographic Seinen
Original run May 26, 2009 – October 26, 2017
Volumes 20 (List of volumes)
Synopsis: The series takes place four years after the events of Magical Girl Lyrical Nanoha StrikerS, during which magical girl Nanoha Takamachi rescued and adopted a young girl named Vivio, who is the clone of the Sankt Kaiser, Olivie Segbrecht. After entering her fourth year of elementary school, Vivio is given her own intelligence device, Sacred Heart, and gains the power to transform using her adult Sankt Kaiser mode. She soon comes across a girl named Einhart Stratos who, similar to Vivio, is the descendant of another Sankt Kaiser ruler, Claus G.S. Ingvalt. As Einhart becomes determined to prove her fighting style is the strongest, Vivio befriends her and, together with her friends, enters a martial arts tournament where they fight against various magical opponents and learn more about their past lives.

https://en.wikipedia.org/wiki/Magical_Girl_Lyrical_Nanoha_ViVid
https://myanimelist.net/manga/14238/Mahou_Shoujo_Lyrical_Nanoha_ViVid

This is a really underrated series. A vast world, great characters, awesome action, and had the best yuri couple in Japanese media. And the funny thing is that this is just a spin-off, staring the daughter of the main character of the previous seasons.
New edit: Recently news of Discotek licensing one of the movies (Reflection).