Had an idea for a story. Not sure if a good one. I KNOW! I'll ask r/mylittlepony

So I enjoy writing, and wanted to use MLP for inspiration. However, I'm only really good at writing darker pieces. And sword fights, for some reason I'm really good at sword fights. I just found this show recently and an idea struck. I just don't know if it is at all a good idea, so I ask you people.

Taking place about 20-25 years after the current series, some sort of cataclysmic event has put earth in contact with equestria. (for my purposes, earth is modern, except people still use swords, guns never happened) Human settlers set out into equestria to explore and set up several colonies. While the ponies and humans were able to coexist for a while, after about 5 years, tensions began to mount. The humans were expanding their territory and trying to take over.

It was a non violent struggle, waged with diplomacy, until one of the ponies' representatives was killed by the human delegation at a meeting. This started the first war in the history of equestria.

My main character is an OC human (feel free to suggest names) who defected to the other side. Not long after he did, quite a few others joined him. Because he used to be one of the most respected fighters on the human side, he quickly rose to a high rank in the equestrian army. Twilight eventually decided to give him magical ability, deeming him "Pure hearted enough to use it for good." While the ponies will fight, they don't want to, thinking it to be evil. Even the main character hates it. Twilight asks him at one point "do you still use my power to serve good?" to which he responds, "No, I use it for the greatest of evils, necessary it may be, but evil nonetheless."

As it currently stands, the equestrian army is losing.

For her logistical and magical skill, twilight is currently the commander of the army, and the head of the magician's corps.

Rainbow Dash is the leader of the aerial troops. Her recklessness has been effective, but left her with many scars, including one that almost completely obscures her cutie mark.

Fluttershy is the head of the army's medics, being the most talented healer in the land.

Rarity was found to be fairly useless in battle, but her fashion skills have been put to use designing armor. She is now the chief armorer in the army, creating the best armor ever seen.

Applejack is the head of agriculture. She makes sure the army is supplied with enough food. She is the most experienced farmer, and as such tends to be more hands on than the others.

Pinkie Pie is Twilight's chief adviser. She has shown to be more sensible than her careless and aloof nature may suggest. Her suggestions have saved the entire army more than once.

The main character is the commander of all ground troops. He is also another of Twilight's advisers. Because he is the most experienced, and most skilled swordsman in equestria, he is also Twilight's personal bodyguard.

Let me know what you think or if you have any suggestions. THANK YOU EVERYPONY!