In the time before the sister princess, before Equestria, there was war between the types of ponies.
 
A lone pony in full plate mail stood on a hill, looking over a field. Her mane and tail moved with the breeze as she looked down at the camp. A smile spread on her face, "They are coming along good. The bow training will help if the Pegasus decide to attack." A voice could be heard behind her, "Lady Steel! Lady Steel!" Her head snapped to the side as she looked for the source of this intrusion. An earth pony with a tan body and a green mane and tail came running up. He wore leather armor and had a bow on his back. "Taut Strings...what Is the meaning of this?" He was out of breath as he stood before her. "Lady! I Have something for you!" Her head cocked to the side, "Then give it to me solider!" He nodded and walked  to her to kiss her cheek. She gave a slight smile. "Strings...what Did I tell you about that?" He chuckled and rubbed the back of his head. "Just...wanted To give you that...for luck. The scouts say that a squad of Pegasus and Unicorns are both heading this way." The smile on her face was cold and void of joy. "Come, let us go to my tent, call the officers, we will plan and be ready for them." His head nodded quickly. "Yes, Lady Steel."

Midnight Steel, or Lady Steel is the Knight Commander of Chancellor Puddinghead. She leads the troops from the front lines and oversees their training. She had risen through the ranks with hard work. She always put the job first, and was feared for her ability to use a sword.  Her troops, some feared her, some admired her, but they all showed her respect. She is a pony that put her job before anything else, but there is a rumor going around that Steel is sweet on Taut Strings, but no pony dared say it to her face.

The sun rose over a tented field. The pegasus came in from the west, the unicorns, from the east. As the two armies charged each other, and the Earth pony camp in the middle, the tents were destroyed, and the earth ponies were nowhere to be seen.  The fighting armies did not notice, they were too busy fighting each other. From the hill overlooking the field, Steel stood, her ponies behind her. She raised her sword, "ARCHERS, READY!" The lines of archers, led by Taut Strings ready and raised their bows. "KNIGHTS, READY!" The regiment of knight ponies lined up, pawing the ground. She smiled, "ARCHER! FIRE! KNIGHTS" She trust the sword forward, "CHARGE!!!" The arrows flew, and the knights charged, Steel at the head of the charge. Unknown to Steel, a group of unicorns turned, it's leader pointing. "Stop her and we stop them all!" The group began to focus their magic on the charging leader. So intent on the battle, she did notice them, until, "RELEASE!" The bolt of magic flew across the field of battle, slamming into Steel. With all the unicorns focusing on different spells, the mana covering the earth pony merged, and ran wild. Strings sat on top of the hill, and fell to his knees as he saw the spell ht his commander, the pony he...loved. "No....." The ball of mana that was once Steel surged, and a detonated, sending a shock wave across the field and through the air, knocking down every pony it hit. Inside the ball of mana, Steel screamed and cursed herself for falling into a trap. She felt the mana burning into her, and as the mana exploded, she blacked out....emerging and falling into a place far removed from her time.

 
Update

Midnight Steel has left the employ of Princess Luna. She has wed Crimson Resolve, becoming the Empress to the Ibexian Empire