Cursed

Zatanna and Bruce stepped into the penthouse, soaked from the rain.
Alfred was ready with a towel as they arrived.  "I thought you might end up soaked," he said to Bruce, picking up an second towel for Zatanna off the counter.
Bruce didn't answer.  He took the towel and kept walking.  From the mere look on Bruce's face, Alfred could see that something had gone wrong.  He also knew, however, that he wasn't likely to get an immediate answer from Bruce.  He turned to Zatanna instead.  "What happened?" he asked concernedly.
"Bruce nearly got mugged in an alley..."
"My word!"  Alfred looked at Bruce, but he seemed to be alright.
Zatanna's eyes widened as she remembered the rest of the details. "And there was somebody out there dressed like a giant bat!"
Alfred frowned with suspicious confusion.  He didn't see how a lunatic in a costume mattered in this situation.
"He was up on the fire escape, just staring down at us.  And then when we took out the last mugger, he jumped up and flew away on his wings!"
At this, Alfred was startled.  He'd seen many things in the past few months that he couldn't explain, including at least two people that didn't need any wings at all to fly.  He was quite ready to believe Zatanna's story, incredible as it was.
"...What—or who—do you think it could have been?" Alfred asked.
Zatanna was completely at a loss. "Alfred, I've seen a lot of things in the last year; things you wouldn't believe."
Alfred half-smiled wryly. "Oh, I wouldn't be so sure about that..."
She ignored his remark. "...But I don't have any idea who or what that was."

"Cursed..."
Zatanna and Alfred turned to Bruce, who was standing in the middle of the living room.
"What was that?" Zatanna asked.
"I'm cursed," Bruce replied.
Zatanna and Alfred looked at each other in confusion.  Bruce was never superstitious in the slightest.  In fact, as far as either of them knew, Bruce didn't believe in anything beyond what was clearly and readily comprehensible.
"What do you mean?" Zatanna said gently, walking up behind him.
He turned around to look her in the eye.  "Ever since I was a boy, I've been... stalked... by bats.  When I was a child, they wouldn't leave me alone at the manor.  My father dressed as one for Halloween on the night he was murdered.  And now this one follows me tonight."
"So you think you really are cursed?"
Bruce was surprised that she seemed to be taking this seriously.  He frowned.  "I don't believe in magic, or anything like that.  But there's... something... something that won't leave me, no matter where I go."
She tilted her head to the side and raised an eyebrow, her lips curved into a clever smile.  "You don't believe in magic?"
"No."
She smiled a little wider. "Really... then how do you think I stopped that last mugger?"
He narrowed his eyes at her.  "What are you saying?"
She paused for a moment.  "My father wasn't just a stage magician.  Turns out he knew real magic."
Bruce wanted to roll his eyes.  The Zataras had always tried to convince him to "believe in magic," but he never thought they were actually serious.
She continued.  "...and if you'd like, I can see if there are actually any spells or anything of that kind on you."
He sarcastically decided to humor her.  "Fine.  Let's see what you can do."
She halfway-scowled at his attitude, but took a deep breath and mentally prepared to do her work.  She took two steps backward, and looked Bruce over a couple times.
"Alright then.  First things first.  Yrd sehtolc."
Zatanna's clothes and hair fluttered for a moment, then suddenly appeared completely dry.
Bruce stared at her quizzically. "Did you just say 'dry clothes' backwards?"
"Yes," she replied matter-of-factly. "That's how I have to say my spells, at least until I learn how to do them otherwise.  Now shut up and hold still.  Erutinruf raelc eht moor."
The living room furniture suddenly slid to the sides of the room, leaving Bruce standing alone in its center.
She took another step backwards, shut her eyes, and stretched out her hands towards him.
"Laever lla cigam."

A circle of bright light began to glow on the floor beneath Bruce's feet.  Without warning, the room suddenly became a storm.  Lights of purple and gold spun throughout the room, casting a powerful glow that shone brightly through the windows of the tower.  Wind swirled about Bruce, knocking over nearby objects but leaving Bruce firmly planted where he stood.  Alfred was thoroughly shocked by what he was seeing, and stood, stunned, against the back wall of the room.  Bruce would normally have been weirded out by all of this, but he wasn't.  He could feel the magic's power delving deep into his soul: into that part of him that held on tight to the pain of his past.  He let that pain overtake him, and he stood firmly within it.  The magical display around him couldn't break his mental state.

The elevator door dinged, and Diana stepped in.  Seeing what was happening, her eyes suddenly switched from surprise to fury.
Zatanna felt her shoulder grabbed by a painfully tight grip.
"Witch!"
Diana spun Zatanna around, slamming her back into the wall and holding her there by the throat.  Zatanna, stunned, looked at Diana.  Her eyes were burning with a warrior's rage.
"Miss Diana! Miss Diana!" Alfred said, running up from behind.  "I assure you, Miss Zatanna is a trusted friend.  Please, unhand her!"
Diana wasn't convinced.  "Where I come from, witches are slaughtered on sight."
Still taking her by the throat, Diana dragged Zatanna across the room back towards the elevator door, where Diana had dropped her bag.  She reached inside and pulled out her lasso.  She wrapped it around Zatanna's shoulders and pulled it tight.  "What are you doing to him?" Diana asked, pointing at Bruce.  She removed her hand from Zatanna's throat.
Zatanna coughed and gasped furiously for several seconds before she could respond.  Her voice was cracking and weak. "I'm testing... to see if there are any magical curses upon him. I'm just trying to help."
Diana took a deep breath, and stood up, loosening the lasso at the same time.  "Very well.  You may continue."
Zatanna stood up, rubbed her throat, and gave Diana the most intense "WHAT THE HELL?!?" look she could muster.  Before she could finish walking back across the room to Bruce, the center window in the living room shattered.  Zatanna winced, then opened her eyes to see Clark standing in front of her, peering suspiciously down into her eyes.
"Who are you?" he asked.
"Alfred says she's a friend," Diana said from the back of the room.
A gust of wind and a red blur announced Bart's sudden appearance in the penthouse. "Who's a friend?"
Clark turned to Alfred.  "Is everything alright?  I saw bright lights coming from the windows.  It looked like trouble."
"That's what I thought," Diana said again. "But apparently this... witch... is trying to help somehow."

Zatanna looked over her shoulder at Diana.  "Please, honey, lighten up on the 'witch.' I prefer 'Mistress of Magic.'  Now, all of you, MOVE!  Dnib elpoep ot moor's egde!"
Diana, Bart, and Clark were dragged towards the walls by an unseen force, only stopping once they were standing at the room's sides.  Clark was shocked.  Even when he tried to fly, he couldn't move an inch closer to Bruce.  He'd never met anything that could physically stop him from moving before.

Now Zatanna could get back to her work.  As she concentrated, the winds and light began to calm somewhat.  Things were getting clearer.
"There aren't any spells on him," Zatanna said.  "But... there's something else.  It's not magic... it's something deeper."
She focused harder. "Laever siht rewop."
Gently, through the rustling and howling of the winds, the whispers of a child's voice could be heard.  "...I swear... ...their deaths... ...the rest of my life..."
Zatanna's eyes widened with surprise.  "...It's an oath."
Half-turning to everyone else, she explained.  "He did this to himself.  I don't know how, but somehow it's connected to him.  It comes from him."  

Bruce's body began to darken, as though it was being overtaken by a shadow.  His eyes opened, and glowed red.
"What are you doing to him?!" Clark yelled.
"...Nothing," Zatanna replied. "This... this is him.  This is the darkness inside him.  It's manifesting itself physically."
Zatanna stepped towards Bruce curiously, gently putting her hand on his cheek.  "What are you?..."
He spoke.  His voice sounded deeper, older, and filled with power.
"I am vengeance."
The vortex around Bruce began to swirl faster.
"I am the night."
A bright light gathered behind Bruce, settling into a solid shape.  Everyone in the room felt its power; its intensity.  It was fierce; it was predatory; it was darkness.  It was the symbol of a bat.  The winds increased to terrifying speeds as Bruce opened his mouth to speak again, threatening to tear the walls of the tower apart.
"I AM—"
"Lecnac siht lleps!"

The spell stopped at Zatanna's words.  The winds ceased, the lights faded, and Bruce went back to normal.  He fell to the floor, completely unconscious.

Everyone in the room was honestly too confused or frightened to move anywhere near Bruce.  Everyone but Zatanna.
She knelt at his side, lifting his head onto her lap.  Now she knew what had driven him all these years.  Gently stroking his hair, she cried for him.