Author's Note: This is by far my favorite episode of the Justice League cartoon show. The idea of Superman crossing that line is so wonderfully disturbing. This was originally posted on AO3. I hope you enjoy it!

Pairing: Pre-Superbat.

Warnings: Graphic depictions of violence and talk of severe mental health issues are in here. If you can't handle that sort of thing I would advise finding something else to read. I wouldn't want to make any one uncomfortable or trigger them. Have a nice day.

Disclaimer: I don't own DC comics characters.

"Do you have any books on the human brain? Specifically anatomy, but all information is good information." Clark said as he entered the monitor room of the Watchtower.

Bruce turned around in his chair, "I never got rid of any of my parents' things and I'm sure dad- …Why would you need that information in the first place?"

"Why would your father have anatomy books? Did it have something to do with a hobby or profession of his?" Clark inquired.

Bruce narrowed his eyes, "Not important. I'll ask again. Why do you want those books?"

Clark leaned against the wall and crossed his arms, "Just humor me."

Bruce sighed, "He was a surgeon. Now answer the question, Clark."

Well, fuck. He didn't mean to actually say Superman's real name out loud. He wasn't supposed to know things like that. Bruce bit down on his tongue hard as punishment.

"Clark. Clark. Clark." He tasted the word as if it was from a foreign tongue he had never heard before. "I didn't think you knew my name… That was foolish of me to assume now that I dwell on it. You probably know almost everything about almost everyone on the Justice League. Tell me, what else do you know about me?"

A lot. Bruce knew a lot about him. Too much even. At one point Bruce was what some people would call obsessed. What did they know anyway? Just because Bruce knew how Clark took his coffee to the exact contents of his closet didn't mean he was obsessed.

Bruce hesitated, "Clark Joseph Kent. You're a reporter for the Daily Planet who more often than not shares a byline with Lois Lane. You live in a small top floor apartment with nothing unusual in there whatsoever. As a newborn you were adopted by Martha and Joseph Kent, an infertile couple of farmers living in Smallville, Kansas. You were a straight A student that almost never got into any trouble. I can go on if you want."

"Wow. How exactly did you get some of that information?" Clark asked letting his natural Kansas drawl shine though.

Bruce might have rolled his eyes, but it was hard to tell with those creepy white lenses, "It was actually too easy to figure you out. Disappointing. I was expecting a challenge."

"You're so intelligent." Clark smiled softly.

Clark had always admired Bruce's brains. Sure Clark was technically smarter, but in a different way. Bruce was only human while Clark was practically a god. Bruce's intelligence was inspiring.

"Off topic flattery. Why do you want those books?"

Clark began to walk towards Bruce, "You know so much about me. Yet I know nothing about you. The fact that your father was a doctor is the only thing I really know about you." Once Clark was right in front of Bruce he placed a hand on Bruce's face, "What color are your eyes? How old are you? What is your name? Tell me about your family."

Oh so many questions that he had lost the right to ask and expect real answers to.

Once upon a time Bruce would've willingly shared all of this information and more with Clark if had prompted it. He might've of even liked the hand on his face. Now the questions and the hand just felt like insulting invasions.

Once upon a time Bruce used to trust Clark. Now Bruce trusted nobody.

Bruce batted Clark's hand away, "You're avoiding the question."

Clark let out a huff of air, "Fine. I've noticed that you've been a little uncomfortable recently. I'm not sure exactly why. I came up with a silly hypothesis. It was ludicrous, really, but I couldn't think of any other possible reason. So, on the off chance I was somehow correct with this ill founded line of thought I have a plan that would put your mind at ease."

For some reason Bruce's comfort was still a major priority to Clark. There were a million other things that were technically more important, especially in these times, but Bruce was still very high up in his mind because Bruce was… something to Clark. Clark wasn't exactly sure why a man that he barely knew anything about meant so much to him.

Perhaps he didn't want to lose another teammate? No. That wasn't it. It was true, but it was not the truth Clark was looking for.

Human life was beginning to lose meaning to Clark. Human life was no longer a precious thing to cherish. Human life was now just a toy or a game. An admittedly sorta fun one at that. No one seemed to notice, but maybe that was because no one wanted to notice. Who would want to think of Superman like that?

Yet somehow Bruce's meaning didn't decrease. If anything, Bruce's value had increased in Clark's eyes. He was a precious thing to cherish instead of the fun toy or game almost everyone else had become. Bruce's heart beat was the only one he listened for before he went to bed anymore.

So he came up with a plan to make sure Bruce wasn't uncomfortable. Lobotomizing villains with his heat vision. Clark didn't think it would be nearly as fun safe for the public as just killing them, but if that was what it would take to make Bruce happy he would do it gladly. Besides he would still be able to kill them at first with the excuse of needing more practice.

Bruce didn't speak for a while. When his voice finally managed to work again he was even quieter than usual, "You've started executing villains, and you that I'm just a little uncomfortable."

It was almost insulting to Bruce that Clark could be so blind.

Clark blinked and took a half a step back, "I was right. Rao, I didn't expect to be. Who would've known taking out the trash made Batman squeamish?"

"You're killing people!" Bruce growled.

"Such harsh words. All those people deserved it, Sunshine." Clark said as he pulled up a chair across from Bruce.

Bruce shook his head, "That doesn't mean it isn't murder."

Clark sat down in the chair, "Again with the words that carry negative connotations. Now that I think about it you have probably never taken a life. Not once. We need to have a conversation on why you are you adverse to it."

Bruce's left hand became a fist, "That. Is. Not. Up. For. Discussion."

It used to be up for discussion between them. It really did. Bruce used to feel he could say almost anything to Clark. That feeling had disappeared in recent times.

Clark laid a hand on Bruce's fist, "Please. I want to understand you better."

Determination was a trait Clark prided himself in having. Today he was determined to learn more about what should be his.

Sometimes when Clark was soft and gentle like he used to be it gave him a spark of hope. It made Bruce less uncomfortable in his presence.

Bruce unclenched his fist, "I made a promise to myself that I would never take another life no matter what."

Clark tilted his head, "No matter what? Even if they deserved it?"

"That's what I said." Bruce gritted his teeth.

Clark frowned, "Why?"

Bruce looked away, "I have my reasons."

"It doesn't make any sense to me and it won't make any sense until you tell me all of those reasons." Clark said gently.

Bruce knew exactly where this was going to go. Clark would find ways to poke holes in his reasoning. Make him doubt himself. Make him okay with killing.

Against his better judgement Bruce looked at Clark once again, "When I was a little boy my parents were shot down in front of me."

Clark leaned forward and wrapped his arms around Bruce, "You poor thing. That explains so much."

It explained why Bruce was so paranoid. Why Bruce was so depressed all the time. Why Bruce even decided to be a superhero.

Some little punk traumatized him.

Clark didn't think anyone had the right to hurt Bruce like that.

Clark didn't say it but Bruce heard, "That explains why you are such a freak."

Bruce attempted to shake Clark off with no success, "I don't want your pity."

He got enough pity in his actual day to day life. From the moment his parents died on all anyone had ever shown him was pity. It got old.

Clark squeezed tighter, "But don't you see? That is why I kill, darling. People like the person who shot your parents should be eliminated."

Bruce raised an eyebrow, "Darling?"

Clark laughed nervously, "I don't know your real name."

"Get off of me. Now." Bruce ordered.

Clark let go of Bruce with reluctance, "Sorry. But that person deserves to die as does everyone like them."

"That is not up to me." Bruce said.

"But-"

"And that brings me to another reason, doing bad things doesn't necessarily make them a bad person."

"Lex Luthor was a bad person." Clark said with confidence.

Bruce nodded, "He was. But is Harley Quinn a bad person because she fell in love with a bad guy that manipulates, twists, and abuses her? Is Poison Ivy a bad person for loving plants with all of her heart because they are the closest thing she will ever have to children? Is Mr. Freeze a bad person because he so desperately wants his wife to live that he would do anything?"

"Don't you miss Flash?" Clark asked. He couldn't find a way he could answer those questions without insulting Bruce so he changed the topic.

"I do." Bruce said, "I do. I miss Wally a lot."

"Wally… so that was his real name." Clark said slowly.

"Wallace Rudolph West." Bruce confirmed.

Clark's voice was strong, "Wallace Rudolph West. Isn't he worth killing for?"

Bruce looked down, "…As much as I miss him… as good of a friend he was to me… I still can't kill for him. I can't because if I kill I won't- I can't."

"If you kill you won't…?" Clark rested his chin in his hand.

Bruce bit his lip, "Be able to stop. I'm afraid to let go. If I kill I would probably love it. I would get addicted. I would become a serial killer. I wouldn't be any different than the most heinous villains."

Clark smiled with a kind of warmth and familiarity that Bruce thought he would only be able to see in the sweetest of dreams as he reached for Bruce's face yet again, "Oh darling, it's okay. You can let go."

Bruce had a hard time believing that Clark actually told him letting go would be okay. Clark, the Big Blue Boy Scout. Clark, the dorky reporter. Clark, the sweet farm boy. That Clark was encouraging Bruce to kill for hedonistic reasons.

One could argue that that Clark was gone. Gone and never coming back. That Clark died in the Oval Office alongside his greatest enemy.

Now we have a new Clark. A Clark that manipulated people. A Clark that would take basic human rights away from people. A Clark that loved to kill.

It was one thing to kill for the greater good, and it was another thing to kill for fun and claim it was for the greater good.

Bruce could imagine what it would be like to let go. In fact he pictured it often. That may not of been the healthiest course of action. Most serial killers report fantasizing about torture and murder before they actually do it, but Bruce couldn't always help himself.

Picking the victim would be an interesting process. To avoid Clark turning on him all of his victims would have to be some sort of criminal. He would probably be able to compile a nice list every time he talked to a Gotham City cop.

He would definitely stalk his victims for days. Bruce liked to learn as much as he could about everything so why would it be any different with killing. Bruce would know absolutely everything there was to know about the person before he finally tied them up.

The screams of his victims would come to feel like music. The kind of music that gets you pumped up while being soothing at the same time. Deep down he was sadistic and twisted and he knew he would enjoy knowing his victims were in pain.

Blood. He would have so much fun with blood. It would get everywhere. He would smear it across the walls, and maybe even write messages with it. His hands would get completely soaked every time. The carpets would be stained forever. A little trail of it would drip down his chin because he would probably love it enough to drink some of it.

Cleaning up would be less fun but sadly necessary. Bruce would very good at it at least. He was so detail orientated that he wouldn't leave until he had meticulously scrubbed all of the semen out of all of the places it could possibly be and destroyed all of the fingerprints.

Despite all of this clean up he would still leave a nice, bloody crime scene. He would set up the body as a puzzle the homicide detectives would spend their entire careers trying to figure out and never quite grasping it. The press would probably give him some name that he wouldn't like all that much. That name would end up in the unsolved mysteries file where it would stay for all eternity.

And Clark would be by his side every step of the way. He would support this hobby. Clark would probably be the one actually picking the victims after all.

Oh god, Bruce just see Clark smirking and saying, "Go ahead darling. I love to watch you work." while slipping a hand down his pants. Clark would be a witness to all of the terrible, horrible tortures Bruce would put his victims through. And he would probably like it.

Old Clark would be appalled and horrified if Bruce did these things, but new Clark might even join in sometimes. They would play with the blood together. New Clark might enjoy making out in a puddle of blood. New Clark would probably fuck him into that same puddle. Old Clark would've thrown him into Arkham if he found out Bruce thought this way.

It was so tempting. Oh so tempting. The bloodlust in Bruce's heart could only truly be satisfied in one way, and he knew it. But resisting sweet temptation was something Bruce had mastered over the years.

Now Clark was leaning towards him slowly and shutting his eyes as he grabbed Bruce's face. He was going to try to kiss him. Bruce knew it.

Bruce wanted to kiss Clark. He really, really did. Bruce had been harboring feelings for the man for a long time. Longer than he would willingly admit to anyone. And if Clark kissed him he would melt into the kiss. But if Bruce melted into that kiss that would mean surrendering. It would mean becoming Clark's. If he was Clark's than he would lose control of what happens next, and everything that Bruce had imagined would happen. He couldn't let that happen. It didn't matter how he felt about Clark.

Bruce got up and left.

Author's note: Thank you for reading this! It was a lot of fun to write actually. Any questions, comments, criticisms, concerns, or opinions in general? Did you really love it or was it the worst thing you have ever read? Just wanna talk to me? If so please leave a review. I love reading anything you have to say.