Joker and about ten of his men walked into the room containing Poison Ivy's cell. It was filled with a thick red mist that made it impossible to see inside. Joker didn't know what it was for, and he didn't care. He tapped the end of his metal walking stick on the glass and moved his head over to the intercom.

"Hello? Anybody home?" he asked in his usual joyful voice.

Ivy then appeared from the mist and approached the glass. She was surprised to see Joker; nobody had said anything about him in a long time. "What are you doing here Clown?"

"What? Didn't you hear my big radio debut?" His smile didn't waver. He already knew her answer.

She raised a confused eyebrow. "No, I didn't." She didn't like where this was going. Then again, she didn't like anything that involved the Clown Prince of Chaos.

He let out a long fit of hysterical giggles. "Then this'll all be new to you!" He continued laughing as he and his men turned around and left. Ivy now knew that he was going to try and kill her.

Ivy pressed her hands firmly on the glass and shouted after the clown. "What are you doing you freak?! What's your scheme this time?! Tell me what you're up to!"

Joker just continued laughing uncontrollably and strolled out of the room with his men in tow. She then felt that something wasn't right in her cell. She was suddenly feeling... sick. She turned around and saw that the red mist that usually filled her cell was slowly being replaced with a green one.

XXXXXX

Batman jumped out of the Batmobile and sprinted towards Arkham Mansion. He had to track down two separate men who were extremely dangerous as quickly as he could before one of them began killing everything in his path to get to the other. Just as he was about to storm through the front door, a man went flying out of a window from inside and landed in the rain. Batman looked over to the nearly unconscious man; it was clear that he had been through hell just then. Suddenly another man jumped out of the window the first had gone through, and Batman recognized him instantly due to the black spiked arms. Mercer landed about ten feet behind the other man, who Batman looked closer at and saw that he was a Joker thug. The goon was now on his hands and knees crawling away and begging for mercy. Mercer raised his right claw in the air and then drove it into the ground. In the next instant a tight cluster of gray spikes shot out of the ground and impaled the thug. The spikes were so large that when the receded back into the ground and Mercer took his claw out as well, the man was in two pieces.

Mercer paid no mind to the man he had just brutally killed. The man worked for and killed for a genocidal clown who was nothing more than a rabid animal Mercer needed to put down. He flexed his claws and began walking away. He didn't get far before something captured his undivided attention.

"Mercer!"

He froze in place. Even though it was raining cats and dogs, and the thunder never stopped, Alex was positive that he had just heard someone call out his name. His real name. He turned around rapidly in circles, the noise of the weather made it impossible to know where the sound originated, to see who knew he was Zeus. He looked all over the darkness ahead of him and saw nothing. He then looked behind him towards the front steps of the building he had just scoured looking for the Joker. He was relieved and surprised to see Batman; he thought it would have been a military officer or a reporter. He and the Batman stared into each other's eyes for a moment, and Mercer broke it off when he walked away towards another one of the buildings to continue his hunt for his white-skinned prey.

"How do you know my name, Batman?" Mercer knew that the Batman wasn't going to just let him walk away and turned his head to the side and sure enough, the Dark Knight was walking next to him and looking at him intently.

"Most people wanting to keep a low profile while conducting their plans might use a fake name when checking themselves into an asylum." Batman replied with nothing but seriousness.

"Yeah, I guess so," Alex said realizing his mistake. "Anyway, we both know why the other is here, so let me say that he isn't in the mansion."

"How many men did you kill inside it?" While Batman was somewhat grateful for knowing that Joker hadn't been found by Mercer yet, he still knew how Mercer was conducting his search.

"I don't know. You think I keep count?" He knew what was about to be said to him, and he didn't wait to hear even one syllable of Batman's lecture on the wrongs of killing. "Listen, you can either follow me around and fruitlessly try to coax me out of my way of doing what I do, or you can do what you really want and go and try to find the Clown before I do."

Batman saw Mercer's point and decided to act on it, but first he had to know something. "Do you see what you do as fun?"

Mercer stopped walking. "No..." He cracked his neck and again flexed his claws. "I see it as necessary." He started moving again. He began running and disappeared into the darkness and the veil of water.

Batman was relieved to know that Mercer didn't kill for his own amusement, but still wished he could somehow convince the antihero that he should never take a life. He admitted to himself that the Joker needed to be found, favorably by him, and turned around and ran off in the opposite direction Mercer had towards the Intensive Treatment building.

XXXXXX

Joker made his way around the Intensive Treatment building all while laughing to himself with his mouth closed. Whenever he crossed paths with someone, he nonchalantly shot them and either killed them or left them to die. He was hoping that what he heard had been true about Zeus.

"That guy and Batsy could throw one helluva party!" He cackled to himself. He casually walked further and further into the building, wondering who would find him first; Batman or Zeus.

XXXXXX

Mercer crushed the doors to Specific Treatment with a flick of his clawed wrist. He walked in and looked around for any more Joker goons. He found none, but that only made him more alert. He also took note that they had apparently shut off the power since it was almost completely dark except for a few emergency lights that lit up every room and hall dimly. He walked through the many twisting and turning halls, still not finding anyone. He was standing in the middle of one of the halls, thinking about whether or not to just make the building collapse on itself. He decided against it when he heard a very frantic and disturbing voice behind him.

"Yer a demon! Yer here to rape my soul!"

Alex turned around and saw what was obviously a loose inmate. He had on shredded pants, no shoes but socks, a torn straight jacket so that his arms were free, and a white cloth wrapped around his head. He was standing about thirty feet away from Mercer, looking at him with blatant fear. He then became very angry looking.

"Well maybe I kill ya an' rape ya with ya own freak arms!"

Mercer held up his still clawed hands and gestured for the possible lobotomy patient to slow down. "Sir, I want you to turn around, walk away, and forget you saw me." he said in a calm voice. He didn't want this man to rush to his own grave, and he really didn't want to kill anyone who wasn't killing anyone else.

The inmate seemed to ponder and consider Mercer's request. Then he began running towards Alex with his arms flailing all over and his voice screaming like a wild mad animal. When he tried to punch Mercer, the clawed predator dodged him without effort. The inmate then turned around and again tried to land a blow on Mercer all to no avail.

Mercer knew he had to find a solution to this as fast as he could. He was wasting valuable time with this inmate, but he had to find a complex and difficult to achieve way to end this without killing him. He was so deep in thought that it took him a second to realize that the rabid screams of the inmate had ceased. He felt something on his left arm, and looked over to see that inmate was no longer with him; he had tried to tackle Alex to the ground and charged right into his spiked arm, which impaled him in several places all along his upper body and head. He was so stuck on Mercer's arm with all the black thorns that were still inside of him that Alex had to slide his other hand between the inmate's body and his own arm, and pushed him away and off of him. Mercer spent one second looking down at the world's newest corpse before moving on, making his way deeper into the building. He had chosen not to kill the inmate, and yet the man still wound up dead. Things had to change... quickly.

He made his way through several rooms, not running into anyone else for a long time until he reached a room that led even deeper into the dark maze, and also led to the control room of the entire building. He was about to simply go the way that led him further in when he heard two voices in the control room. He walked up to the door and decided to listen in on them before deciding whether or not to take them out. Maybe they could reveal a clue as to where the Clown was.

"Why do we have to stick around here guarding a stupid container? All it's doing is pumping something into the vents."

"What're you complaining about? We're getting paid in full, and all we have to do is sit here until she's dead. Best part is that long as we stay quiet, the Batman probably won't find us with the power out."

"Well what about that Zeus guy I heard about? What if he shows up?"

"You kidding? He's probably locked up in here himself. Hell, I'll bet the boss'll run into him in that Intensive place or whatever it's called."

"Alright alright. You sorta have a point... say where's this stuff being sent to anyway?"

Satisfied with now knowing which building to look through, Mercer prepared to smash the wall in when the next thing one of the goons said stopped him dead.

XXXXXX

Batman crept along silently the halls of Intensive Treatment. He had taken out at least twenty of the Joker's men, and one of them even told him that the Joker inside the building. For some reason, the Joker had demanded that the power be shut off on the entire island. This was a foolish choice; the Clown had given Batman a very distinct advantage. He slowly made his way to a hallway of nothing but cells, and heard an all too familiar voice.

"Mistah J! Ya came to get me, didn'tcha?"

"Haha! You could say that Harl." The Joker slowly reached into one of his pockets and grasped his trusty revolver. He got ready to pull the weapon out and rid himself of Harley forever, but he was struck in the side and then pinned to the wall by his neck. The impact had caused him a great deal of pain. He raggedly breathed and looked down slightly to see a familiar cowl. "Hello Batsy. Didn't think I'd see you here."

"You basically told me where you were going with that broadcast." Batman replied in his usual voice. "Why the sudden lust for the limelight?"

"Well I just got it!"

"What are you talking about?" Batman tightened his grip on his rival.

"Right now! You put all your thoughts on me, and came running!" He laughed painfully due to the iron hold on his neck. "You see, I decided to see how my old buddy Zsasz was doing, and he tells me that Zeus put himself in here! So I chose to put on a little show to catch his attention and to see how fast you would come to my rescue! I didn't have a doubt that you knew he was in this hellhole the whole time. And I knew you wouldn't let some spikey freak take your best friend away from you.

Batman had known this insane man for many years, and yet he still knew so little about him. He killed on pure impulse and by choice. He never thought about the safety of anyone, including his own. He didn't care how many people he killed to get what he wanted.

"Sometimes I just don't know why I let you live, Joker."

XXXXXX

"Poison Ivy's cell."

"Why are we pumping the boss's gas into her?"

"It ain't the gas, it's-" Before the thug could complete his answer, Mercer smashed through the wall and chopped both of them to pieces; one got the lower half of his body amputated and the other wound up with four silver talons coming down on the top of his head. Enough said. Mercer looked over to the side of the room and saw a large liquid container with a horrendous smiley face painted on it. On the top of it was a valve and a hose that was connected to one of the many pipes on the wall. His claws cut the hose like kite string.

He sprinted out of the hole he had created and made his way to Ivy. Mercer realized that with Joker in Batman's hands, Alex would have another day to get his claws on the psychotic clown.

"When I find you Joker, you're going to be my scratching post and punching bag for a long time."

XXXXXX

Ivy could barely breathe. The green mist that had now completely fill her cell wasn't Joker's signature Laughing Gas, but it was still deadly to her. She raggedly breathed as she held one hand on her stomach, and pressed the other hand on the glass wall of her cell to help keep her upright. Whatever the gas was, it made her feel like she was completely engulfed in a blue-hot fire.

One of Joker's thugs had stayed behind earlier, and he basked in watching her slowly die. He stood right up to the glass in front of Ivy. He had been taunting her for a while, although she clearly heard him, she had hardly paid any attention to his rambling; the only thing she had registered was that he claimed he going to 'have a lotta fun with her' after she died.

Ivy was just about to lose what little strength she had left and fall over when the thug suddenly stopped talking. She looked up and saw that three small swords were stuck in the glass, and they were coming out of his neck. The blades receded out of the glass and the goon, and the dead henchman fell to the ground to reveal Mercer with his clawed arms standing in front of her now. He took a few large steps to his left, and drove his clawed fist into the glass. It shattered into thousands of pieces. He stepped through the gaping hole he had just created and turned his arms back to normal. He ran over to her and picked her up bridal style. He turned on his heels and ran out of the green haze, which was making some of his biomass drip off of him.

"Don't die on me," he said to her as he ran through the large building making a beeline for the front door.

"Just don't drop me," she replied with a small smile. Over the course of her latest and his premiere incarceration inside Arkham, he had visited her custom cell everyday and the very first thing he said to her after calling her his winter rose was 'Are you alright?' After that, they slowly developed an actual relationship after admitting that they provoked each other to try and kill the other and realized that there were several similarities between them. She was well known and feared as an eco-terrorist, and Blackwatch had labeled him a bio-terrorist. Neither of them were human, and both were seen as monsters. Both of them had the ability to reinvent the world around them. They were both victims of what they had been researching when they were still just themselves.

Mercer was thankful that the rain had since stopped as he ran out of the building but soon skidded to a stop when an extremely strange black car pulled up in front of him. The door opened and Batman stepped out and looked at him and the barely conscious Ivy.

"We don't have time for you, Batman!" Mercer shouted in anger that he had lost all his momentum.

"It's not me who should be your concern," he replied calmly.

"That right goes to me." A voice to Mercer's left said. He turned to see a middle-aged woman surrounded by a small platoon of elite soldiers armed to the teeth. "Alexander J. Mercer. Codename Zeus."

"I'm not impressed miss. What else do you got?" Mercer shot at her. She was wasting his time; he could feel Ivy dying in his arms.

"Whoever dealt with you last time burned and erased everything else, but I know enough to know you're a force of nature and can be an extremely valuable asset, so you now work for me."

"Says who?" Mercer now wanted to tear her apart. Nobody owned him or told him what to do.

Before she could answer, Batman walked up next to Mercer and spoke up. "I know what you're up to Waller, and it's a very bad idea."

"Oh really? And just what do you know about him, Batman?"

"I know enough to guarantee that he'll kill all of you where you stand without a second thought if you keep wasting his time."

"Really?" She gestured to her soldiers and all of them aimed their primary weapons at Mercer.

"You don't want to do this Waller," Batman knowingly warned her.

"Listen to your Batman Waller, and I'll let you keep your head." Mercer added.

"Fire." Waller said. All the soldiers fired one shot into his head. They all stood completely still with their mouths agape as they watched him remained standing and alive.

He looked at them with fiery hatred not just because they had shot him, which he found to be very annoying, but they ran the risk of hitting Ivy. "Hold her." He said to Batman who took Ivy with tremendous care. He turned back to his new prey and formed his blade on his right arm and claws on the left.

XXXXXX

A/N: In the Arkham Asylum video game, it is clearly stated by Riddler that Joker can somehow make contact with the inmates while he is loose.