I don't own anything
Spoiler warning. This story covers all seasons of Supernatural and other things.
Jack Kline, son of Kelly Kline and Lucifer, the new God, was sitting on a park bench in a small town in Missouri with a content smile on his face as he looked around at the world around him.
As he sat there a figure appeared near him and walked over to the bench he was sitting on and stopped in front of it and the figure said in a female voice "We need to talk."
Jack looked up and said "Hello Billy."
Billy, former reaper, and current Death of this world looked at Jack and said "We need to talk. Will you come with me."
Billy looked at her a moment and said "Is this about the other Death returning. Aunt Amara told me she felt him appear not to long ago."
Billy pursed her lips and said "Yes. He wishes to see you. He has asked if you would bring Sam, Dean, and Castiel as well. He wanted me to tell you it is not an order but a request. He said he has a favor to ask of the 4 of you and only ask that you will listen to his request. He said he feel's that he at least is owed that much."
Jack tilted his head to the side and said "I will come listen to him and I will ask Castiel to join us but Sam and Dean have earned their piece."
Billy said "Will you at least pass on the request to them and let them choose for themselves."
Jack looked at her before he looked around and said "Very well. I will pass on the message."
Billy said "Then I will wait for you at the gates of Heaven." before she disappeared.
Jack took one last look but had a frown on his face before he also disappeared.
In heaven, Sam and Dean were sitting on the hood of the Impala drinking a beer while looking out at a lake they were parked beside when the sound of wings fluttering were heard and both men turned around and saw Jack and Castiel standing by the back of the Impala.
Dean said in a shocked voice "Cas...Jack...it's good to see the both of you. Want to join us for a couple of beers."
Castiel had a concerned look on his face and said "Sam...Dean...it's good to see you both but I'm afraid this isn't a social visit." as he first looked at the men before he looked at Jack.
Jack sighed and said "I did not want to interrupt your peace here in heaven because you have more then earned it, but I was approached by Billy. The previous Death, the one you killed Dean, he has returned and has asked to have a meeting with the four of us. Billy claimed it is not an order but just a request to meet him and hear him out. She said he feels that he has at least earned that much. I tried to have you both left out but Billy asked me to at least give you the option of listening to his request."
Sam and Dean both glanced at each other a moment before Sam nods his head and Dean chugged the rest of his beer before he looked up at Cas and Jack and said "Where do we go."
A short time later the four of them appeared at Heavens Gates and saw Billy standing there who said "Sam, Dean, it's been a while boys."
Sam said "Billy."
Billy waved her hand and suddenly all 5 of them were at a pizza place and everyone saw Death sitting at a table and he motioned toward the seats and said "Please, sit." before he picked up his fork and knife and took another bite of his pizza.
Everyone took a seat around the table and Death said "I am sure you are all wondering how I am alive and why I have asked you here. The answer is the multiverse is bigger then you can ever imagine. I am not just A Death. I am THE Death. The original. The one all other Deaths answer to. This is but one tiny little universe in one tiny little section of the ever growing multiverse. Chuck, the previous God of this universe is but one of many Gods. Have you never asked yourself, if God created everything, where did the Pagan gods came from."
Death took a sip of soda and then looked at Sam and Dean and said "I helped you boys more the you might think, like when you were dying after you refused to complete the last trial. You were dead Sam. I should have took you but I kept you alive long enough for your brother and that angel to get you to agree to keep on living. I knew that you had a larger part still to play which is why I personally came and stalled as long as was needed. That was but one time I helped you boys."
Death cut himself another piece of his pizza and took a bite and after chewing it he looked up at Jack and said "You are a young God and even with your Aunt advising you, there is still much for you to learn and do. You must expand your territory and create new universes to replace those that Chuck destroyed in his tantrum. If you do not then the power you are currently gaining as the God of this universe will become to much and you will explode destroying not only yourself but all life in this universe. That is why I have came here to help you."
Castiel said "Help him how."
Death said "Well there is the hard way, the easy way, and then the amusingly easy way. It is the last I have decided to start teaching young Jack here first. The hard way is having you learn to starting from scratch with every spec of dirt in a new universe having to painfully focus on each and every detail of every creation while also keeping yourself focused on your home universe and making sure it isn't destroyed either by your actions or the actions of another. The easy way is to get another god to allow you to copy their universe but the problem with that is they will often want access to all of your universes which is what happened here and why you have so many pagan gods running around. Pagan doesn't mean they are evil. it means they are immigrants on vacation you could say. The problem with that is that any gods you let come here have the ability to possibly destroy your universe unless you make some kind of deal that prevents them from doing so which often times comes at a price of something you won't want to deal with."
Death took another bite of his pizza and after taking a drink he said "Lastly we have the amusingly easy way."
Dean said "Which is."
Death looked at Dean and got a small smile on his face and said "That's why I like you Dean, despite your fear of me, you still have the courage to smart off to me. The answer is simple, do what you have already done. You took this universe from Chuck, why not take all the other universes from Chuck before he destroys them. You have time travelled and visited alternate realities several times. Just do both at the same time." as he pulled his hand from his pocket and slid a piece of paper across the table toward Jack.
Death said "That is the spell you would need to use in order to visit the alternate realities Chuck destroyed years before he did. There are rules though you must follow if you chose to do as I have suggested."
Jack asked "What rules."
Death said "First, you, yourself will not be able to directly interact with those worlds yourself. You were lucky that Chuck had destroyed all his other universes he created or you all would have failed. As long as even one copy of him exist then that copy could have prevented your from succeeding. Chuck was so arrogant in himself that he destroyed his own safety net. That brings us back to rule one. If you use that spell then the Chuck of that universe will still be the god of that universe. You will have to drain him of his power without him finding out until you are more powerful then him."
Death took another sip of his soda and said "That is where the other 6 of you come in."
Sam blinked and said "Six of us."
A male voice from the corner of the room said "Hello boys, miss me." causing everyone to turn and look at the corner.
Dean said "Crowley."
A female voice said "Don't just stand there Fergus, let me greet the boys also. Hello boys."
Sam said "Rowena."
Crowley said "Mother, Really." as he turned and glared at where Rowena sat.
Death cleared his throat and said "You can all have a big reunion later. I have more important things to do so listen. Jack here can not go to these other universes himself until he is ready to replace Chuck in that universe and leave a copy of himself to take over managing that universe. That is where the 6 of you come in. If you agree to my plan then here is what will happen. The spell I have given Jack open to another universe that is exactly like this one except it will be around the time Sam would be about to leave to head to college."
Death took another sip of his soda and said "None of you have a body that you can use to enter that universe though so what would happen is you would touch the portal Jack creates and you will pass out in this universe while your soul would travel through the portal to that world and would wake up in the body you had in that world counter part. Castiel, you are the exception to this as you did not have a body at that time. However as many times as your were killed and brought back, you soul will now build it's own body as long as your soul exist. You would still pass out here but once you merged with your counterpart there you would within a short time form a vessel for yourself."
Dean frowned and said "And what exactly would we be doing there."
Death said "First, you should know that your souls will be marked and the copy of me of that universe will already know about this and Billy will begin taking over as the new Death of that universe. I will still act as the figurehead of Death in that universe in order to distract Chuck but if you die as long as you have a vessel you will be brought back to life. Jack could also create you bodies if he has gained enough power from that world if need be but that does not mean you should..." as he paused a moment to think.
Billy said "You just remembered who you were actually talking to."
Death said "Yes...you should at least try not to die to many times. As for what you are going to do. That is why it will be amusing and easy. Disrupt Chuck's plans. The more energy Chuck has to use to deal with his story changing outside of his control is the more power Jack will be able to absorb. The choice of what to do is up to you. Now you are aware that Chuck can spy on you anywhere in that universe...but there is a way around that."
Castiel asked "How."
Billy said "Your souls will be marked as Death mentioned. This mark can only be able to be seen by Death so nobody but Death will know it's their. This mark though is a key. That bunker you boys loved so much. You go to it and place your hand on the lock and it will open for you but it will not enter the bunker of that universe. It will enter one in a pocket dimension created by Death for you. It has everything your original bunker had and once you are able to get into the bunker of the universe you are in, everything inside it will be added to your private bunker. That means that for Chuck, he will see you enter but the moment you enter he will not be able to find you. He will waste time and energy trying to spy on you."
Sam asked "What about our internet connection to that world. I mean there were many times where we spent time there gathering information for cases."
Death said "I believe the term is Wifi. The Wifi in your private bunker is more advanced then any other you could imagine. It will be maintained by your friend Charlie who will have access to your bunker. She has agreed to create you, your own personal server that she will catalog all the data in your bunker for you. She has agreed to create your own secure laptop computers and has created for you, your own unlimited credit cards. Jack will be able to visit you in your bunker but will not be able to enter the other universe until he is ready to take over. The reason she has agreed to do this is Chuck killed her and her mate when he destroyed the other universes. When she's not at the bunker she will be spending time with her mate."
Dean said "Now hold on, we have not agreed to anything yet."
Sam said "Dean, you..."
Dean interrupted him and said "No Sam, listen. I know this sounds like a good deal but remember the nest where I died. We got cocky and suddenly boom, I'm dead, for good."
Death said "The mark that will be placed on your soul will be made by Jack, Amara, and myself. Your souls will be immune to anything in any of the universes you visit that were created by Chuck and I will not let you visit any that were not made by him or Jack. If you are ultimately killed and can not be revived in that universe you will just wake up back in this one where you can go, enjoy your peace until you get bored and then go to another universe created by Chuck. That is why there are 6 of you going. A demon, angel, witch, reaper, and a pair of hunters. Between the 6 of you and the knowledge you all have, there is no reason anything in that universe should be a problem for you unless he blows it up which means you wake up back here again while Jack gains all the power that Chuck wasted before he blew it up and if he is powerful enough he can prevent Chuck from doing that."
Dean glared at Death for several moments and until Sam placed his hand on Deans arm and said "Dean, we will be back out there saving people and hunting things. Think of all the things we could do different. All the lives we could save that we weren't able to."
Dean looked at Sam for a moment before he looked at Death and said "I want unlimited pie and my baby...and what about you Crowley. How do we know you won't screw us over."
Crowley said "After everything we been through, you don't trust me."
Dean said "Hell no."
Crowley said "Fair enough. Truthfully, I have no reason to screw you over. Death has made me a deal to good to pass up. My own private universe and a visitors pass to any universe in the multiverse after Jack has taken over all Chuck's universes."
Sam looked at Rowena who smiled and said "Death gave me my son back and a pass to visit his private universe."
Crowley who had an amused look on his face before suddenly frowned and turned to Rowena and said "WHAT."
Rowena said "What, can't a mother come visit her baby boy Fergus."
Crowley turned to glare at Death who said "You never said anything about keeping others out of your universe when we made our deal Crowley. Devil's in the details."
Crowley said "A deals a deal...I can respect that but I'll be sure to be more careful with any deals I make with you in the future Death."
Jack said "What if I don't want to do this. I don't want to take the chance they will have to suffer again like they did."
Death said "That is your choice but there is always a price. My price is simple compared to others you will have to make in order to learn what you must."
Jack frowned and Castiel placed his hand on Jack shoulder and said "I think I speak for all of us when I say we all agree to do this."
Jack said "What about any friends, family, or allies they make in these other realities. I do not want to see them hurt by being separated from them."
Death said "Any that they wish to be included in the secret must sign their name in a special book in the bunker. This will mark their soul to not only prevent them from being able to reveal the secret but also when they die they will be linked to Jack's universes so they will be able to be visited by them."
Jack looked in thought for several moments and said "Very well. If everyone agrees then I will also."
Death said "Then we have a deal."