Manga about about a soldier fighting large scale space battles

Question

This is a black and white manga that I read in English recently, but on the internet. The original language might not have been English. Mechs aren't a thing, but armored vehicles do exist. I only got to around chapter 30, but below is my summary of the plot.

At the beginning of the story the main character is a black haired kid, and he meets another kid who becomes his best friend. This kid is beautiful (according to the dialogue), and has this shiny white hair. The best friend's sister is similarly beautiful, and the main character guy even runs away from her when they first meet.

They all grow up, but then one day the sister is sold off to the Emperor by her father, leaving behind a cake she baked. The main character and his best friend vow to get her back by taking control of the whole universe. They sign up to be officers in the Empire's military, go through school with top marks, then get assigned to a cushy position far behind the front lines. They request to instead go straight to the front lines, where a cabal of fellow soldier try to assassinate them on the orders of a duchess, who dislikes how the sister is taking up all of the Emperor's attention. The main duo power through, and are fairly successful.

They then go up into ships for space battles, where hundreds of thousands to millions of people die in each engagement. There is a giant laser called something like 'Thor's Eye' that is occasionally important. Occasionally, the duo return to the sister, and are sometimes given rewards by the Emperor for their results on the battlefield .

Answer 1

Is this Legend of the Galactic Heroes (FUJISAKI Ryuu)...?

Five hundred years ago, Rudolf von Goldenbaum united the disparate governments of humankind and established a mighty human empire, a tribute to his own greatness that stretched across the galaxy. Demanding loyalty and discipline, Rudolf created an order designed to long outlast his own rule; but all human works fade in time. Today, the decaying empire faces the threat of the Free Planets Alliance and military leaders on both sides jockey for power in the face of a seemingly inevitable conflict. On the side of the empire, the young general Reinhard von Lohengramm sees war as an opportunity, and the empire as soft clay ready for his own sculpting. On the side of the alliance, would-be historian Yang Wen-li would like nothing better than to live out his days in peace - but times of war have little use for men who waste their days studying the mistakes of the past. Circumstances will make heroes and villains of both these men, as they write new history one blood-splattered page at a time.

In the first chapter, we're introduced to two boys; Siegfried Kircheis, a dark-haired commoner, and Reinhard von Musel, a fair-haired boy of noble descent who's described as being 'beautiful' in a caption.

Reinhard has an older sister named Annerose, and Siegfried quickly becomes friends with both of them, but Annerose is subsequently sold by her father to the Kaiser, under threat of being executed if he refused. Just before being driven away, she kisses Siegfried on the forehead and tells him that she baked a chocolate cake that morning.

Reinhard later enrols at the Imperial Military Preparatory School and convinces Siegfried to join him, so that they can take over the universe and get his sister back.

Much later in the story, there's a space battle involving a fortress with a powerful gun referred to as Thor Hammer.