The Legend of Yin and Yang

Clash of Warriors

Wither packed up a few of his things, preparing for his final battle against Spectra. He kept his armor on and his True Night's Edge equipped, but also geared up with a few other things to hopefully make the fight easier for him. Unfortunately, Wither knew the odds of him returning in one piece - if he returned at all - were very slim.
Night tried to convince him to stay, but Wither told her that had no choice - he had to fight for their safety, for the sake of the Corruption.
Zale bid him farewell, and wished him good luck.
Putting on a long cloak over his armor, Wither stepped out the door, prepared for the journey ahead.

After a week-long trek through harsh terrains (he was especially worn down from the Jungle), Wither finally reached the edge of what used to be the Corruption - there was death everywhere he looked. He even saw the lifeless corpse of the Eater of Worlds, meaning that only he, Night, Zale, and possibly the Destroyer were the only Corrupt beings left in the world.
Almost as if he knew he was coming, Spectra dropped down in front of Wither from the sky. He was wearing Hallowed Armor, and was holding the True Excalibur - a weapon feared by all who followed the Corruption.
"Well, well, well," Spectra said, "look who we have here. A lone little Elite? How adorable."
Wither stared straight into Spectra's soul, making his opponent feel uneasy.
"There's nothing you can do to stop me, kid. Now that I have harnessed the power of Terra, nothing stands in my way and survives!"
Wither pulled off the cloak, revealing the True Ancient Shadow Armor. He held the True Night's Edge proudly in his hands.
Spectra's eyes widened. "Wha... how?!"
Wither pointed his sword at Spectra. "I am the Omen. And you are to be exterminated."
Spectra charged forward, attempting to impale Wither, who easily dodged the attack, countering with a cursed fireball to the back.
Spectra turned around, angry. He fired a few light beams from his sword before flying up.
Wither tried to block the beams, but they were too fast for him to do so, hurting him badly. He prepared the Hoverboard he had found, and flew up after Spectra.
Noticing he was being followed, Spectra threw down a few grenades, hoping to hit Wither. The grenades missed badly, and Wither eventually caught up to Spectra. The two clashed swords, until Wither was kicked off of the Hoverboard, onto a floating island.
Spectra flew after Wither, and stabbed him in the chest.
Wither could hardly breathe - the pain was unbearable.
Spectra pushed the sword in deeper.
"Not so tough now, are ya?"
Wither's armor started glowing, and the True Excalibur's energy was sucked into the armor, reverting it back into a normal Excalibur.
"W-What?! That's impossible!" Spectra screamed.
Wither pulled the sword from his chest, and stood up.
Spectra took a few steps back, as Wither fired a dark beam at him, badly injuring him.
Wither stabbed Spectra through the chest, ripped the sword out, then decapitated him.
The absorbed energy reformed into the first sword, which he held in the hand opposite to the one he was holding the True Night's Edge in.
He attached the broken sword to his back, and picked up the Excalibur.

After another week, Wither made it back to the Pedestal. He returned the broken sword to its proper place, causing Terra to appear before him.
Wither knelt down respectfully.
"You have done well," Terra said. "You brought back the first sword, and killed off your only true threat."
Terra stood Wither up.
"There is no need to kneel before me. Your success is all that matters to me right now."
The remaining two swords compressed into orbs, then flew into Wither's sword. Six more, smaller orbs flew out of the Pedestal, then into his armor.
"Now, you must restore the Corruption to its former glory, Omen."
Much to Wither's surprise, Terra knelt down before him, as if he was the God.
"You are well deserving of my respect," she said.
"Great Terra, I don't need your respect," Wither responded. "As long as I have my friends around, I'm happy."
Terra looked up at him. "Your friends were taken hostage."
"W-What?!"
"They were brought to the Lihzahrd Temple. Plantera is awaiting your presence."
Wither was very, very angry. It was fine for Plantera to be challenging him. That was one thing. But to take his friends hostage was a whole different story.
Wither prepared to head off to save his friends.
"Wait, Omen," Terra shouted.
Wither, looked back as Terra walked up to him.
"I almost forgot something."
She started glowing, then transferred energy over to Wither.
He felt yet another surge of power.
Terra ended the transfer abruptly. "I gave you powers of my own. Now go. Save your friends."
Wither nodded reluctantly, and disappeared in a puff of smoke.