Author's Note: So, in the comics, Klaus was also telekinetic, and was powerful enough he caught the 40,000 ton meteor with his powers and saved the world. A Klaus in full control of his powers would be terrifying.

Not to mention, the way he's ridiculed by the whole family - none of them believe the one with the powers to see the dead is actually speaking to their dead brother. They doubt him in everything he says, and yeah, he's a junkie, but he's also their brother and they should know the reason he became an addict was to escape from his horrible ability. Just because most of the rest didn't wind up with something awful doesn't mean they should be able to act high and mighty!

And it does bug me that Ben is also derisive to Klaus at various moments throughout the show despite obviously knowing more about what was done to him and what he experiences (he references the mausoleum, and as Klaus sobers, he's also able to see the hoard haunting him). He even basically outright says Klaus should've died instead of him (which, yeah, in line with the whole 'ghosts haunting Klaus aren't meant to be nice and supportive, they're supposed to be awful and vindictive' but still - that really rubbed me the wrong way).

A Klaus who is vindictive in his own right, angered at the way he was treated his whole childhood, with no support but that of a psychotic spirit - well, it's a frightening idea. The limits of what he is capable of haven't really been explored, so here's one potential. A Klaus who knows his power, is in control, and lacks the morals to hold back.

(He learned from the best after all, and he isn't just speaking of his mentor. Reginald Hargreeves was a mean bastard who cared for very little - what can he say? He takes after his father.)

...

...

According to Father's records, Number Four has been seeing the dead since he was first acquired by Hargreeves. Of course, he didn't work out that was what was happening for quite a time afterwards, but Number Four would scream for hours, babble at things that weren't there, and just overall seem as though he was hallucinating.

Number Four has known he was seeing the dead since before he even had words. They would scream at him, claw at him with their intangible fingers, and whisper him secrets in the dead of night. Some specters were nicer than others, but all had the gore from their deaths painted across their bodies.

His favorite of all the corpses was missing the lower half of his jaw and the back of his head, but his words never seemed garbled. He never screamed or wailed or clawed at Number Four, but instead called himself a teacher. Frank taught him all about the world, how disgusting of a place it was. He taught him that people were horrible and awful, and the only way to survive was to manipulate and use them before they could use him.

Four didn't believe him at first - he loved his brothers and sisters even if they weren't always the nicest to him, and Father was… well he wasn't the nicest, but he cared about them, truly! And then Number Four said something Number Three didn't like, so Number One beat him bloody, so Father expressed his disappointment (Number Two nodding along), so at 7 years old he had his first "private lesson."

Sitting in the mausoleum, still bruised and broken, corpses screaming all around him, Number Four nodded along with every word Frank spoke. Numbers Five, Six, and Seven hadn't been involved but had all seen what had happened, and none of them cared about him. So why should Four care for them?

Father claimed that they were meant to save the world someday, but Number Four found he didn't really care about the world, or the people in it. As he came to this resolution, cracks formed in the cement, and dust swirled in the air around him. He met Frank's eyes and grinned. Obviously this wasn't a development they would tell his Father about, but that didn't mean they couldn't train him up on their own! But first - the screams were really getting on his nerves. Number Four narrowed his eyes, grasped at that place of power he had felt a moment ago, and when he looked again, only Frank's mangled grin stared back.

.

.

Klaus spun the chair in circles as he waited, staring listlessly at the ceiling. "I'm so bored!" He groaned, finally stopping the spinning and throwing his feet up on the expensive desk in front of him.

"Patience, my boy," Frank spoke from the corner.

"You could just forget it! Drop it and go home, find something else to do!" Ben suggested, placing his face directly in front of Klaus'.

"Revenge," the mob taking up most of the room groaned or screamed out nearly in unison.

"Looks like you're overruled again, Benny," Klaus grinned manically.

Klaus dug through the desk in his boredom, and stumbled across the remote for the television. He had just hit the power button when the office door at last swung open.

"Finally!" Klaus stood, throwing his arms open. "Do you know how long you made me wait!?"

"Who are you? How did you get in here?" The overweight, balding man in front of him grouched out forcefully, obviously surprised by Klaus' flamboyant appearance and presence in his chair.

"Wouldn't you know, I'm your four o'clock!" Klaus bared his teeth at the man, laughing to himself.

His eyes flitted to the clock on the wall nearby which read "7:34."

"Get out! Don't make me call security!" The man moved further into the room, unknowingly moving straight through the mob of ghosts crowing for his blood. Klaus' eyes followed the three corpses dogging his footsteps. They hadn't been there previously, and at his silent command they spat out their purpose.

"Now, now, Mr. CEO. I think we can help each other. And believe me, you want my help," Klaus smiled kindly at the man. "You see, I know all about your illegal side business, that whole deal with the orphans, the slave labor, how you dump their bodies in that landfill in Guam…" as he spoke, the man's beady eyes filled with fear, and he began to sweat and turn red.

"Now see here-!" he began storming forwards.

Klaus held out the hand inscribed 'HELLO', and the fat body easily froze in place. "No, you see here." A flick of his fingers, and Jonathen Crofton flew into one of the chairs across from him. "You've been doing some dirty business and getting very rich off it. I would almost applaud you, except you seem unaware of some of the consequences of it. Some of your victims aren't too happy with you. Silencing all of them through murder seems like a good plan, unless there happens to be someone they can go and whine and complain at - oh, wait." Klaus' hand glowed blue, and he could see the moment Crofton registered what had happened. Now he could see the mob as well. He left Ben and Frank invisible for his own reasons.

"What - what is this?!" Crofton demanded, paling dramatically.

"These are just a few of the people who were killed on your orders, Jonny, and as I said before, they aren't very happy with you." Klaus dropped his hand and sat back down in the high back chair, although the wailing spirits clawing and spitting remained visible.

"What do you want?" Crofton stuttered out.

Klaus gave a genuine smile. "I'm so glad you asked." The room silenced although the shapes remained. He set a barrier around them so they could conduct business in peace. "I want 4%."

"Of - of what?"

Klaus rolled his eyes. Of course the CEO was slow. "Your profits. Your business. Your salary. Your bank account."

"That's preposterous!" Crofton gasped out.

Klaus rolled his eyes again. "Oh, please. You would hardly notice it. And do you think this little show is all I've got? I know where their bodies are. I know where more evidence is. I could tear down your whole company with one phone call. I could ask for a whole lot more than 4%."

Frank smiled his viscous half smile of approval at him, while Ben continued trying to talk him out of what he was doing. He did love his brother (in his own way), but Christ on a cracker he could be annoying!

Crofton licked his lips, obviously thinking through his options. "4% and you'll go away?"

"I warn you against attempting to get rid of me like you did the others, Jonny. Those three who you took care of personally. That really came back to bite you." Klaus released some of his power so that the only spirits now visible were the three who had initially followed Crofton into the room. He had actually been present for their murders. They had heard him give the orders. Now they were haunting him and slowly sapping at his life force. While Crofton certainly hadn't been healthy before they started, he hadn't quite been so unhealthy. "You've seen my power over death, and I warn you I won't stay dead even if you are successful in getting that far. I won't be going away. But I will sweeten the pot for you. These three are malignant spirits. They've been slowly killing you. Give me my 4%, and they won't bother you again." The dead looked furious and betrayed, but Klaus ignored them.

Crofton took in the room, his situation, and then finally nodded. "Agreed."

"Wonderful!" Klaus stood happily, pulling the papers out of his jacket. "Just sign the contract, and I'll be on my way." He straightened out the papers, slammed them on the desk in front of Crofton, and then handed him one of the man's own shiny pens.

Crofton moved hesitantly, cautiously picking up the pen, glancing around the room where the vengeful ghosts were banging against his barrier, and then signed everywhere he pointed without reading much further.

It did take Klaus some effort to force all of the spirits he had used in this venture into the afterlife, but he had long since become an expert at hiding the strain and he could see the moment Crofton experienced relief from the removal of his leeches.

"Pleasure doing business with you. My lawyer will contact yours to ensure you follow the agreement. But I warn you, I still have eyes on you. You even think about double crossing or betraying me, and a few angry ghosts will be the least of your worries." Klaus used his telekinesis to cut off the man's airflow for several moments, and then released him.

Klaus moved to exit the room, when he paused at the sight of a familiar image on the television he'd been ignoring up to this point.

"Moments ago, police reported the death of the most eccentric and reclusive billionaire, Sir Reginald Hargreeves," the newscaster reported.

Klaus laughed out loud, then continued on his way out of the office, having to keep a careful restraint on his power so he didn't start literally walking on air.

"So Dad's dead. I guess that means it's about time for a family reunion, eh Ben?" Klaus grinned at his dead brother's disappointed face, even as the elevator took him to the ground floor of the oil company's massive skyscraper.

He would deliver the expected paperwork (guaranteeing his 4% of everything as negotiated… and another 4% every month for 13 months, granting him the controlling share of the company. He'd bleed it dry then cut it loose, like he'd done before with these revenge schemes) to his lawyers (wonderful fellows, they didn't care how he did what he does, just that he continued making all of them richer), and then it would be back - well, not home, but back to the Umbrella Academy. It had been awhile since he'd seen any of his siblings other than Ben. Almost thirteen years, to be exact. It'd be interesting to see what they had made for themselves.