Three months later...
Twilight walked down the halls of Canterlot Castle. I hope the Princess isn't mad at me for inviting my self over, she thought to herself, a little worried. calm down twilight she thought to her self this is just a social call. She had been planning this trip for quite some time. She walked to where Princess Celestia had said to meet up in her letter. It was in a more isolated part of the castle. She had to wonder why. She came around the corner and saw Luna and Celestia standing by a makeshift stairway with a group of armed guards slowly descending.
"What's going on?" asked Twilight.
Celestia turned to her, and said, "Luna and I can feel something down there."
"What is it?"
"we do not know, we are sending armed guards down to find out," replied Luna.
"You two are more powerful. Why don't you both go?" asked Twilight.
"Because," Celestia replied, "Whatever is down there isn't stronger than both of us. The six guards we sent should have no problem handling it."
After a couple of minutes talking to the princesses they here a rumble and Twilight watched in shock as a wave of red energy suddenly hurled the guards out of the caves.
"Twilight, get to safety!" Celestia said. She stepped in front of her beloved student, her horn glowing and ready to fight. Luna's horn was alight as well. The two sister stood ready to fight. The sound of hoofs hitting the makeshift stairs filled the air before Celestia sees him.
Twilight looked on as a male alicorn appeared from the stairway. He looked to be as tall as Celestia or Queen Chrysalis, but heavier built like Applejack's older brother. His wings seemed to be plated in armor. No, Twilight realized, they're not plated. They were actually made of metal. His mane was black and blood red. His hooves were pitch black and looked sharp. The rest of him was red with what seemed to be black energy swirling on his coat--or maybe it was the other way around. Twilight could not tell. Then she saw his cutie mark. It depicted a sword hitting a shield. What did that stand for? His most notable feature was also the scariest, but at the same time it made Twilight feel sad. His horn was broken. Almost half of it was gone.
He looked at the sisters and shouted with anger, "BRING ME DISCORD!" He fired a beam of red energy. Celestia fired back, and the beams clashed and pushed on each other. Luna didn't not stop to see who wins, and fired her own beam right at him. He saw it, and took to the air. His beam stopped firing as he did so, and Celestia's own beam tore through a wall along with Luna's. From the air he fired in a sweeping motion at them, but they both raised small barriers to stop the beams.
Guards rushed into the room. Unicorns in the front crouched low, their horns aglow and pointing at him. The earth pony guards just behind them blocked the entrance to the room with their spears. Pegasi flew above the front lines. Twilight's brother in the front shouted, "Surrender, in the name of Princess Celestia and Princess Luna!" The male alicorn landed. He surveyed the large group of guards and the princesses before him, and closed his eyes as if to think. Celestia opened her mouth to say something, but then a red beam of energy flew from his horn, putting a hole into the ceiling above them. Without a moment to spare, he took flight through it. The unicorn guards opened fire and a few bolts of magic energy hit him, nearly knocking him out of the sky.
The pegasi flew after him,with Luna in the lead. As Luna gave chase, her mind was racing. Did he say Discord? Yes, he did. She was sure of it. How long had he been down there? He must have had no idea what happened to Discord. That much was clear; he probably thought he was still in charge. If only he would calm down enough to let her speak to him. She was sure she could talk him down.
Without warning, he spun around in the air, unleashing a barrage of magic bolts. They took out several guards, and forced more guards to fly out and catch them before they hit the ground. Luna swerved to avoid the bolts of magic before firing back. One hit him in the chest, and he hit the ground hard. The pegasi surrounded him. Luna landed before him, and Twilight, Shining Armor, and Celestia teleported beside Luna.
"Now, Shining Armor!" Celestia shouted. A small version of Shining Armor's force field surrounded the red alicorn.
"My princess, what are you doing?" a guard asked, shocked.
"She keeping him here," Twilight answered. "What do you think would happen if he got to ponyville?" The guard nodded with understanding.
"Who are you?" Celestia asked.
He looked her in the eyes, his whole body shaking hard. Sweat dripped from his body, and blood oozed from his wounds where magic bolts had hit him. "I am Mar," he whispered before he passed out and crumpled to the ground.