Bruce and Selina stared at Marcus in stunned silence, their minds struggling to process what they'd just heard. Everyone in that world carried mutant genes?
"But if everyone has these genes," Selina said slowly, "why bother distinguishing between humans and mutants at all? Why the conflict?"
Marcus leaned back in his chair, his expression growing more serious. "The distinction is actually quite simple, though the implications are anything but. While virtually every human in that world carries mutant genetic markers, only a tiny fraction ever manifests actual abilities."
The holographic display shifted to show complex DNA helixes, with certain segments highlighted in different colors.
"In most people, the mutant genes remain completely dormant – recessive, as geneticists would say. Under normal circumstances, they'll live their entire lives without ever knowing they carry the potential for superhuman abilities. But their children..." Marcus paused, letting the implications sink in. "Their children have a much higher chance of those genes becoming active."
Bruce's analytical mind immediately grasped the horrifying mathematics involved. "So even if a generation of humans managed to eliminate every active mutant, the next generation would produce new ones."
"Exactly. And here's where it gets even more complicated – most mutant abilities don't manifest at birth. Only a small percentage of mutants are born with obvious powers. The majority develop them during adolescence, often triggered by extreme emotional stress or trauma."
The weight of that revelation settled over both students like a cold shroud. Selina voiced what they were both thinking: "So any human couple could have a child who seems perfectly normal for years, then suddenly develops the ability to read minds or control fire or..."
"Or level city blocks with their emotions," Marcus finished grimly. "You can imagine how that knowledge affected society. Parents lived in constant fear that their own children might become something they couldn't understand or control. Children grew up terrified of their own developing bodies, never knowing if puberty might bring deadly powers along with the usual changes."
The holographic display showed newspaper headlines and protest footage:
"MUTANT REGISTRATION ACT PASSES,"
'"ANTI-MUTANT RIOTS CLAIM DOZENS,"
"PARENTS DEMAND GENETIC TESTING FOR ALL NEWBORNS."
"The human faction – those without active abilities – controlled most of the world's governments, military forces, and economic power," Marcus continued. "Their fear of mutants wasn't entirely irrational. When a teenager having a bad day can accidentally cause earthquakes, society tends to become very nervous very quickly."
"But the mutants were still just trying to live normal lives," Bruce observed.
"Most of them, yes. They hid their abilities, tried to blend in, hoped nobody would discover their secret. Some even underwent dangerous medical procedures to suppress their powers permanently. But fear has a way of becoming self-fulfilling prophecy."
Selina shifted uncomfortably in her chair. "So what happened? How did they all end up nearly extinct?"
"Human fear turned into hatred, hatred into action. Laws were passed requiring mutant registration, then internment, then worse. And eventually..." Marcus gestured, and the holographic display showed those massive robotic forms again, "someone decided the final solution was simply to eliminate the threat entirely."
"But you said they survived," Bruce interjected. "How?"
Marcus smiled slightly, though there was sadness in his expression. "They had help from someone very special. Let me introduce you to Katie Pryde."
The projection shifted to show a young woman with brown hair and kind eyes, her appearance utterly unremarkable except for the way she seemed to phase in and out of solid matter as they watched.
"Katie's mutant codename is Shadowcat, and her ability is matter phasing – she can make herself and anything she touches become intangible, able to pass through solid objects like they're made of air."
"That doesn't sound like enough to save the world," Selina said skeptically.
"On the surface, no. But Katie discovered something extraordinary about her powers during the darkest days of the Sentinel war. Her phasing ability wasn't limited to matter – she could phase consciousness itself."
Both students leaned forward, intrigued despite themselves.
"She could send someone's mind backward through time, allowing them to inhabit their younger body with full knowledge of future events."
The implications hit Bruce like a thunderbolt. "Time travel. She could change the past to prevent the future catastrophe."
"Precisely. When the Sentinels began their final extermination campaign, Katie and her fellow survivors were cornered in a monastery in China – literally the last free mutants on Earth. As the robots closed in for the kill, she used her power to send someone back fifty years, to the moment when the Sentinel program first began."
"But why didn't she go herself?" Selina asked.
Marcus's expression grew grim. "Because the process is incredibly dangerous. The further back in time consciousness travels, the more likely it is to cause catastrophic brain damage in the recipient. Most people would die instantly from the neural shock. Even powerful telepaths like Charles Xavier couldn't survive a trip of more than a few days."
"But someone could," Bruce said, reading between the lines.
"One person. The only person whose healing factor was strong enough to survive having his brain essentially liquefied and reconstructed repeatedly."
The projection changed to show a rugged man with wild hair and retractable metal claws extending from his knuckles. Even in a still image, he radiated barely controlled violence.
"Logan, codenamed Wolverine. His mutant ability is accelerated healing – not just fast recovery, but regeneration so complete he's essentially immortal."
Marcus turned to Bruce with a slight smile. "Let me put his healing factor in perspective. If you suffered a wound deep enough to expose bone, how long would you need to recover?"
Bruce considered the question seriously. "With the best medical care available? At least a month to fully heal, possibly longer depending on complications."
"Logan would heal that same wound in under sixty seconds. I've seen him recover from injuries that should have been instantly fatal – bullet wounds to the brain, having his heart torn out, even being reduced to a charred skeleton. Given enough time, he regenerates completely."
Both students stared at the projection in amazement. Selina found her voice first: "That's... that's impossible. Human biology doesn't work that way."
"Mutant biology does. Logan's cellular regeneration operates at speeds that defy conventional understanding. It's what made him the only viable candidate for Katie's time travel mission – even if the process killed him repeatedly during the journey, he'd simply heal and continue."
"So he went back and changed history?" Bruce asked.
"With my help, yes. I arrived in that timeline just as Logan was beginning his mission. Together, we managed to prevent the Sentinel program from ever beginning, which created a new timeline where humans and mutants learned to coexist rather than destroy each other."
The holographic display shifted again, now showing a very different scene – humans and mutants working together, children playing in integrated schools, news reports about collaborative scientific achievements.
"But that world taught me something crucial about the nature of fear and prejudice," Marcus continued, his voice taking on a more serious tone. "The technology to create Sentinels existed because humans were terrified of being made obsolete by a superior species. When faced with beings who could reshape reality at will, their response was to build weapons capable of genocide."
He looked directly at both students, his meaning clear.
"Sound familiar?"
Bruce felt a chill run down his spine. The parallels to their current situation with Clark and the Kryptonians were unmistakable.
"But let me show you another world," Marcus said, shifting the display once again. "One where the challenges were different but the lessons equally important."
New figures appeared in the projection – people in high-tech armor and costumes that looked more like something from a science fiction movie than a documentary.
"This is Earth-616, though its inhabitants just call it Earth. The man in the red and gold armor is Tony Stark, also known as Iron Man."
The armored figure soared through city skies, repulsor rays blazing from his palms as he battled what appeared to be an alien invasion.
"Tony inherited his father's company and his genius-level intellect, but unlike Howard Stark, he was forced to become a hero rather than choosing it. Captured by terrorists and forced to build weapons for them, he instead created his first suit of armor and escaped."
Bruce studied the armor with professional interest. The technology was clearly decades ahead of anything on Earth, yet somehow it felt familiar.
"His father Howard was one of my friend in that world," Marcus explained, noticing Bruce's attention. "The combat suits you two are wearing were inspired by designs Howard developed after studying captured alien technology."
The projection shifted to show the suits Bruce and Selina wore, then transitioned to display their obvious similarity to armor worn by two figures in the new world.
"But this world was different from the mutant Earth in crucial ways. Instead of one or two types of enhanced individuals, it was home to dozens of different kinds of heroes and threats."
New figures appeared in rapid succession: a massive green humanoid with barely contained rage, a man carrying a shield that seemed to defy physics, a woman with red hair and weapons that belonged in a spy thriller, a blonde man wielding a hammer that crackled with lightning.
"Steve Rogers, enhanced to peak human condition by a super-soldier serum during World War Two. Bruce Banner, a scientist transformed into an engine of destruction by gamma radiation. Natasha Romanoff, a former Russian assassin with skills that border on superhuman. And Thor..." Marcus paused, studying his students' faces carefully, "the God of Thunder from Asgard."
"God?" Bruce repeated, his voice carefully neutral.
"Literal deity. Asgard is one of the Nine Realms connected to Earth through cosmic phenomena that science hasn't fully explained yet. Thor is thousands of years old, possesses strength that can level mountains, and wields a hammer forged from the heart of a dying star."
Selina's eyes widened with sudden recognition. "Wait. Thor? As in Norse mythology?"
"The very same. Which brings me to something interesting about your world." Marcus fixed both students with a meaningful look. "You know of a miracle that occurred in 1984. A man who could grant wishes, and a woman who fought him?"
Bruce nodded slowly. "It caused chaos worldwide. Everyone was making wishes, reality itself seemed to be breaking down. Then this woman appeared – she looked like something out of ancient Greek art, but she could fight like nothing I'd ever seen."
"Diana Prince, also known as Wonder Woman. She's the daughter of Zeus and an Amazon warrior princess from Themyscira. Like Thor, she's a literal mythological figure living in the modern world."
The revelation hung in the air between them. Both Bruce and Selina had assumed the events of 1984 were some kind of unique supernatural occurrence, not part of a larger pattern of divine beings walking among humans.
"The point is," Marcus continued, "in every world I've visited, the same fundamental challenge exists: how do ordinary humans coexist with beings who possess godlike power? Some worlds handle it better than others."
He gestured, and the projection showed scenes of cooperation and conflict from multiple realities – humans and enhanced individuals working together, but also images of fear, prejudice, and violence.
"The mutant world nearly destroyed itself through fear and hatred. Tony's world managed to find a better balance, though not without significant growing pains. Your world..." Marcus paused, choosing his words carefully, "your world is at a crossroads."
The weight of that statement settled over both students. They were being asked to help determine which path humanity would take.
"I've told you about the worlds I've visited and the people I've met," Marcus said finally, "but I haven't explained the most important part of my story. The reason I began traveling between realities in the first place."
The holographic display shifted to show what appeared to be a vast cosmic void, filled with swirling energies and impossible geometries.
"I come from a universe very different from any of these. A place where reality itself is more... flexible. I was chosen to become something called a Void Walker – someone who can traverse the spaces between dimensions, the cosmic emptiness that separates one reality from another."
Images flashed by showing Marcus in various forms of exotic armor, wielding powers that seemed to bend the very fabric of space and time.
Bruce felt something shift in his understanding of their teacher. This wasn't just a powerful individual with mysterious origins. This was someone who had voluntarily taken on the responsibility of protecting all of reality, yet still chose to invest time and emotion in training three children from Gotham.
"Will you leave again?" Selina asked quietly.
"Yes," Marcus replied honestly, "but not for as long this time. And when I do go, I'd like to take you with me. Both of you have the skills and judgment to be valuable allies in other realities, and there's nothing quite like seeing different worlds to expand your perspective on what's possible."
The prospect of visiting other dimensions, of seeing firsthand the wonders and terrors Marcus had described, sent excitement coursing through both students. But Bruce's tactical mind was already working on the implications.
"If we can travel to other realities, we can study how they dealt with similar challenges. Learn from their successes and failures."
"Exactly. Knowledge is power, but wisdom is knowing how to use that knowledge responsibly."
Marcus stood, and the holographic display faded away, leaving them in the comfortable lighting of the lounge.
"Now then," he said with a slight smile, "I think it's time for proper introductions. After everything you've learned about me, you deserve the chance to present yourselves as you truly are."
He straightened, his casual demeanor shifting into something more formal and ceremonial.
"Marcus, your teacher, Void Walker between the dimensions. It's my honor to meet my students again after far too long."
Bruce rose as well, feeling the weight of ceremony settle around them like a comfortable cloak.
"Bruce Wayne, student of Marcus, protector of Gotham City, and the Batman."
Selina stood gracefully, a smile playing at the corners of her mouth.
"Selina Kyle, student of Marcus, guardian of Gotham's forgotten, and Catwoman."
For a moment, the three of them simply looked at each other, sharing smiles that carried twenty years of history, loss, and reunion. In this place between worlds, surrounded by technology that defied understanding, they were simply teacher and students finding each other again.