Summoner's Folly

Simon felt the first flickers of true power creep out of the symbol engraved upon the ground. It's gentle prodding increased in strength as his chanting crescendoed and quickened in tempo. In a climactic finale, his shouting reached its frenzied peak until his voice grew hoarse and the power from the other side was a crazed clawing.
He was panting and drenched in sweat; Simon should have been exhausted. However, true power laid willing at his feet. The euphoria masked his worldly obligations and allowed him to be the true magus he was meant to be. With a final word Simon called out the true name of his demon thrall. "Nagel."
Summoned from the ether, and given name, Nagel reached a gruesome arm through the symbol, now a portal through which it would be born. It heaved itself out, unleashing unbearable shrieks that had no place in the world.
Simon's euphoria quickly dwindled, leaving him with only a nauseous pit in his stomach. He closed his eyes and covered his ears, but the sickly odors of death and brimstone could not be blocked out. If he could have thought coherently, perhaps he would have had misgivings about what he did, but all he could do was topple over and vomit onto the cold cobblestone floor.
Nagel finished pulling itself free of the ether by the time Simon recovered. He reached his arms upward and stretched. The air around him distorted as he exerted his power onto reality, attempting to bend it to his will. The symbols surrounding the demon flared bright crimson red as they rebutted his power.
Simon shook as the final test of his power came to an end. Relief washed over him. The binding would hold. He mindlessly wiped his brow and the smallest fleck of sweat landed upon a rune inscribing the binding circle. He only had a second to realize his mistake.
A second too short. One moment the demon was complacent and docile, then the next a snarling beast tearing a gaping hole out of the smallest breach of the circle.
A gust of power hit Simon squarely in the chest and knocked the precious wind from his lungs. A thousand counter spells flew through his mind as he sped through the air, but without the breath to seal Nagel, none would do any good.
He collided into the wall. Simon was too dazed to watch as his minion shattered the binding. Raw magic exploded like dangerous shrapnel, and while it bounced harmlessly off Nagel, it drove deep into Simon's body. Without breath or voice, the mage could do nothing but fight the blurring edges of his vision as death took hold of his spirit.
Simon wanted to leave his mark on the world. He would be. They would call him Simon, the one who brought Nagel the Destroyer to the material plane. But to Nagel, he was insignificant, not even worth a killing blow. He would die in time, and why end his suffering when there were so many in this new world who had yet to meet their end?