Finn Campbell Mertens stood before a swirling vortex of light, it was a portal to yet another unknown world/time/universe/dimension, he said goodbye to his friends on this world and jumped into the portal. As he flew through this tunnel, he felt like he was in free fall through the center of a kaleidoscope, he remembered the day this journey started and it was all because he couldn't let go of his doubts.
Flashback
Finn was holding on both ends of the severed limb of the Guardian of this cosmic prison, a prison where he found his biological father. He was too reckless, too naive and too trusting, because of that his father and all the prisoners were able to escape, he refused to let go of the Guardian severed limb, both because he needed answers from his father and because it was the right thing to do, he couldn't let this criminals leave.
The cursed grass sword responded to Finn's desire and engulfed his entire arm before creating roots on the side of the severed limb that the escaping prisoners were using as a vessel. He heard his father say something but he was too focused on the task at hand to understand, then he felt the pull of the portal become stronger, he felt his arm snap and then nothing, he no longer felt anything on his right arm.
Finn fell, he saw his father and the prisoners escape through the portal. As he fell on the pool beneath him he saw Jake trying to reach him, but a wave pushed him over the edge of the prison over the void. His last memory before blacking out was of Jake screaming his name trying to reach him.
End of the Flashback
The adventurer came back to reality as he felt a change in gravity, at the end of the tunnel was a portal just like the one he jumped into before. When he passed through the portal, he bended his knees the moment his feet hit solid ground allowing him to roll, good thing he did because trying to land at the speed he was going and the stronger gravity of this world could have broken his legs. He stood up, he reached into his backpack and pulled a scanner, more or less the size of a phone, and activated. Scanning his surroundings it showed a percentage: 99.99999998474758439999987866%.
"I'm getting closer," said Finn to himself. The device in his right prosthetic hand can tell him how "close" he is to his original universe.
When Finn woke up after falling into the void he was in a hospital on a space station with other humans, at first he thought that he somehow was found by a group of surviving humans on Ooo. However he was proven wrong when he was informed that his "energy signature" indicated that he was from a parallel universe, he was informed by a strange man dressed as a bat that called himself Batman.
Finn was found floating near Earth inside a cocoon made of a strange plant like material that originated from the stump that was his right arm, if he had to guess what happened was that whatever was left of the grass sword protected him from the void, it saddened him to know that the grass sword died protecting him. Then he learned about that Earth's histories and heroes, he told them his story and they promised to help him get back home and while he waited he would gladly help the "Justice League" –that's the name of the group of heroes– to protect that Earth.
During Finn's five year stay he learned much in the way of both science and magic –both from humans and aliens alike– to get back home as soon as possible instead of the pursuit of knowledge and it was only in the third year he noticed that he stopped growing. The medical team told him that after his body reached his prime he stopped aging, he was both happy and sad, happy that he would not die of old age before he was back at Ooo and sad because he knew deep down that it might take a long time before he would be able to reach his home.
The only hope that kept Finn going was the fact that the flow of time was different between universes, he hoped that when he arrived on Ooo only a little bit of time had passed, a foolish and naive thought but it was all he had at the moment and refused to even consider the opposite. It took five years but he developed and built the equipment necessary for him to travel the multiverse, the fact that the League had prior experience in dealing with the multiverse helped a lot.
Finn came out of his introspection and stored the device back in his enchanted backpack, with a pocket dimension inside, before inspecting his surroundings. He seemed to be in a dead world, it happened every few "jumps" and seeing no other choice he started to set up camp. Once camp was set up he started a fire and from his backpack he took out a container, not unlike a small cooler, and unsealed the top before taking out a pack of marshmallows.
Good thing Finn knew how to make containers with a pocket dimension inside, because he used them to store almost everything, and for this reason he had a supply of food that could last decades if needed, hell he had a portable bunker on his backpack. After putting a marshmallow on a stick and hold it over the fire with his right hand he stored the "cooler" back in his backpack and with his left hand he reached one of his pockets and took out a small cube, the size of a sugarcube.
"Mother Box how long has it been since we started this journey?" Finn asked the small box.
"In relative time, it has been 15340,5 days," said the Mother Box in a female robotic yet kind and caring voice as she started to float beside Finn.
"I see," said Finn.
This Mother Box was his last gift given to him before he left the Justice League, it was given to him by the High Father of New Genesis after he helped stop Darkseid. This Mother Box was special as it was built to operate beyond the Source Wall, he received her when the High Father informed Finn that his home was beyond the known multiverse, the High Father knew of multiverses beyond the one he protected but he never visited any of them.
Finn visited many multiverses since then, in one he met a guy in armor that could fly called Iron Man, he spent over 7 years on that multiverse and like the first he learned much when it came to science and magic, he also met a guy named Goku that was fighting against a cat god that could destroy worlds on another, he spent over 3 years in that multiverse, he once ended in a world full of ninjas that knew some kind of magic that was given to them by aliens but they called "chakra", he spent 2 years on that multiverse, he saw a world of pirates with power gained from magic fruits, he spent 4 years on that multiverse, he saw a world seemingly made of food with superhuman hunters and cooks that looked for rare ingredients, he spent 12 years on that multiverse, don't blame him the food was delicious and 7 years in a multiverse also with superhuman hunters that could manipulate their own life force, plus 2 years of "jumps".
"Do you have a projection of when we will arrive on our destination?" asked Finn as he reflected on his journey that he was on, 42 years since it started.
"No, it could be on our next jump or many thousands of jumps later, it is impossible to tell, our journey might as well last forever, the megaverse is infinite after all," said the Mother Box.
"At least I get souvenirs of every world we visit," said Finn more to himself than the Mother Box, if wasn't for the fact that she could hold a conversation with him he would have gone mad long ago.
"Power of positive thinking," said the Mother Box as she giggle, yet another fact he was grateful for, the fact that the personality of the Mother Box could change if needed, it kept the conversations fresh and unique.
"Well I better get some sleep, wake me up in 8 hours or if something happens," said Finn as he finished eating his marshmallow and went inside the tent.
The Mother Box glowed, covered the fire with sand using telekinesis and floated in the middle of the camp constantly scanning the surrounding area.
Time skip (many years later)
Finn took out his scanner and heard a ping, he felt tears of joy run down his face when he saw that the scanner showed 100%. Finally he was back in his multiverse, now he just needed a way to the center of this multiverse and from there he could find his way home, to Ooo.
"Mother Box scan this multiverse, find its center," said Finn unable to hide his happiness.
*Ping* *ping* "Scan complete, center found," said the Mother Box.
"Did you find a lifeform on its center," said Finn as he looked at the void with countless geometric shapes floating in it.
*Ping* "Yes and no, there seems to be a lifeform there but its presence is overshadowed by its projection, for lack of a better word," said Mother Box.
"Take us there," said Finn.
Center of the Adventure Time multiverse, Prismo's Time Room
A portal opened in the center of the room where Prismo existed, he looked at the portal with curiosity, it was rare and I mean extremely rare, for him to encounter something he didn't know.
Prismo the Wish Master was the manifestation of an old man's dream, shaped like a giant humanoid shadow with blue eyes that could move on walls, his body sticking to whatever it was on. Essentially, he was two-dimensional but he was aware of the goings of his multiverse. From the portal walked a cloaked stranger, the black hood obscured his face, it wasn't just shadow because the light coming from the wall in front of the stranger didn't reach his face and the rest of the cloak hid his body. Once the stranger was out of the portal, it closed by collapsing into a small box floating and orbiting the stranger.
"Hello Prismo," said the stranger, the voice was that of a young man but tired not unlike a man that came back home after a long journey or war.
"Do I know you?" asked Prismo simply.
"Yes you know me, but I thought you were dead," said Finn as he looked at the Wish master that killed himself to allow Finn to meet his biological father, another regret he carried with him during his journey.
"Yeah, it's like, a long story but the gist of it is that Jake, a friend, was kinda down since Finn's 'death', that was his brother by the way, so he ate a lot and he ate my last pickle so I transported him here he became the one dreaming me and I pulled him before he slept and ta-dah, I was alive again and Jake went back to Ooo," explained Prismo, more or less.
"I hope Jake is all right," said Finn to himself before he pulled back the hood showing his face and long blonde hair.
"Hello Finn," said Prismo as if he just saw him yesterday, which for a fourth dimensional being might as well be true.
"How long have I been gone from my timeline/universe, Prismo? In relative time," asked Finn.
"From the perspective of the inhabitants of your Ooo, it was like a year," said Prismo.
Finn fell backwards but as soon as that started the Mother Box changed into a chair for Finn to sit.
"Wow, I knew that there was a possibility that time might be slower than I perceived, but to actually hear confirmation…" said Finn to himself.
"Not to sound rude or anything like that but you better get going. Actually, why you came here anyway?" asked Prismo.
"It's easier to navigate from the center of a multiverse. Can you summarize my Ooo's coordinates in numerical value using this room as a point of reference?" asked Finn.
"Sure," said Prismo as a long string of numbers and letters appeared on the walls. Just as Finn got up the chair turned back into a box and scanned the walls.
*Ping* "Coordinates acquire," said the Mother Box as it opened a portal.
"That's the first time I see a Mother Box this close," said Prismo just as Finn jumped on the portal.
"Wha-," started Finn but the portal closed behind him. The portal opened on the grassy plains where he lived with Jake, ignoring Prismo last comment he took a deep breath letting the air of Ooo fill his lungs. He was in the grassy plains of his home, it was just like he remembered and dreamed. He couldn't help it as he said to himself as a single tear came out of his right eye, "I'm back."
Finn walked in the direction of the tree house and just on top of the hill next to it he saw a gravestone. There was an inscription on the grave: "Finn the Hero of Ooo, may he find peace wherever he is or go on his next great adventure, whichever he feels like."
Finn knew the grave was empty but the thought that his friends would have buried him here, near the place he lived with his brother, where many of his adventures started, it was a humbling feeling to look at your own grave but at least it showed that people cared. He looked up at the orange sky, behind him was the setting sun, the stars were starting to appear, indeed it was a good place to rest.
"Hey, who are you and what are you doing over my bro's grave?" asked Jake as he approached the stranger and he wasn't alone.
Finn turned his face obscured by the hood to face the newcomers, then he saw his brother and friends. Jake, looked tired and depressed, trying to hide behind him was BMO afraid of the stranger, not far behind them was Marceline, Princess Bubblegum and Flame Princess.
Marceline was wearing a big hat, probably because of the setting sun, a red sleeveless shirt and skintight jeans, brown knee high boots and long light yellow gloves that went past her elbow, the same outfit that she wore when they made a band, her long and her flowing black hair only reinforced the memory of that day.
Bubblegum was wearing a pink cardigan over a short pink dress that went almost to her knees, it was possible to see that she was wearing magenta shorts beneath the dress, on her feet were pink knee high boots and lastly on her head was her crown over her pink gum like hair that was in a ponytail, ironically it was also the same outfit from the "band day".
Flame princess, technically king, wearing her red and maroon colored armor that was the symbol of her authority on the Fire Kingdom, her "hair" was still down indicating that she haven't recovered completely from the poison.
"Whatever you are doing stop and get out, we don't want to deal with some punk today," said Marceline in a rather aggressive tone.
Finn just tilted his head to the side a little, as if to express confusion. Marceline losing what little she had of patience used her axe/bass to attack the stranger, all she wanted was to mourn her friend in the anniversary of his death, a death she knew would happen sooner or later but she hoped it would happen much later in Finn's life, she knew it was inevitable, Finn was mortal after all, still it did not make any easier to move on.
However, before the battle axe could make contact with Finn the Mother Box became a black sword, floated in front of him and parried the axe. Angered, Marceline kept trying to hit the stranger, but the sword would move on its own and parry all of her blows and the stranger would just stand there looking bored. She let her frustration show when she used both hands to hold the axe and used her powers make the muscles of her arms grow. As veins started to bulge she attacked but unlike the other times the stranger raised his right arm and stopped the axe.
The eyes of everyone that was present widen in surprise, but the clank of metal hitting metal was heard when the axe made contact with the palm of his hand. In shock Marceline let go of the axe when the stranger pulled, flipping the axe in mid air he grabbed it with his metal hand, probably a prosthesis or armor because she could smell blood and sweat so whoever and/or whatever the stranger was, he was a living or at very least organic being. Before she could move the stranger held the blade of the axe against her neck and Marceline cursed herself for being reckless but she refused to die today, she won't cause more grief for Bonnie and her friends.
"Wait she didn't mean to do that, she is just grieving and frustrated," pleaded the princess of the Candy Kingdom.
The stranger just flipped the axe around and offered the axe back to Marceline. She looked at him with suspicion before taking back the axe.
"Were you close?" asked Finn without revealing his identity, yet.
Bonnibel noted that the stranger had the voice of a young man but it was tired as if he had a long life weighing on him. This was something that she heard in very few beings, one of which was the Vampire Queen beside her, the voice of a seemingly young immortal who had lived through many years of hardship.
"Yes, he was a very close friend," answered Bubblegum being diplomatic and not wanting to start another fight.
Marceline clenched her teeth but said nothing, then she saw Jake move behind the stranger and enlarge his fist and she smirked.
"Did you love him?" asked Finn to Bonnie wanting to know the truth. So shocked she was by this question that she didn't react when Jake attacked, nor when a hexagonal floating barrier appeared and stopped Jake's fist. Her gaze focused on the stranger, something about him called out to her and she for some reason felt she could trust him.
"Yes, I loved and still love him," said Bonnie without doubt or hesitation.
This answer made Jake jaw drop, literally, even Marceline and FP were shocked at the princess' confession.
"Then why you never told him?" asked Finn.
"He was too young and even if he matured he would still age and die, I thought that it would be better to just be friends for the rest of his life, we would still be close and I could be there for him," said Bonnie.
"And what about you?" asked Finn looking at Phoebe.
"I love him too, but he betrayed my trust and that hurt me deeply. However I would have forgiven him if he understood what he did. Unfortunately as Bubblegum said he was too young and naive, even so I miss him and would do anything to have him back," said FP with conviction as she too felt a strange connection to this mysterious figure as well.
"And you?" asked Finn looking at Marceline.
"What about it?" asked back Marceline.
"Did you loved him or you considered him just a friend that jammed occasionally?" asked Finn.
"Why should I tell you?" Marceline asked back.
"I'm sure he would have understood if all of you told him about your feelings," said Finn, although he knew it would take awhile for his younger self to grasp what they were trying to convey.
"And how would you know, you speak as if you knew him," said Marceline.
"Indeed I knew him, I knew him better than anyone on Ooo will ever know," said Finn.
"That is a bunch of junk, how could you know him better than me, his bro," said Jake pointing at himself.
"Simple, because I am him," said Finn as he pulled back his hood letting his long blonde hair free.
They gasped, before them was a young man with long and silken blonde hair that reached the small of his back, his face very similar to what they remember not counting the scars on his right cheek or the one over his left eye and the fact that it was no longer the face of a child but that of a man, from his right hand that was still extended it was possible to see a glint in the torn glove, result of stopping the axe earlier, it was metal reflecting the last rays of light of the setting sun.
"Long time no see, ladies," said Finn with a calm and serene smile.
Bonnie felt tears run down her pink face as she saw her hero and champion alive a year after his "death". So overwhelmed by her emotions that she did the first thing that came to her mind, she slapped him, hard, very hard. The sound of flesh meeting flesh echoed on the plains, Phoebe approached and slapped him on the other cheek, thankfully she had a fire shield on her.
"Ok, I deserved that," said Finn.
"Finn!" said BMO as it run toward Finn and hugged his leg before saying, "You are back, we have to celebrate with Finn cakes."
"I missed you to BMO," said Finn.
The MB that was floating near Finn lowered herself and got closer to BMO, as BMO looked at the small floating cube.
*Ping*
*Giggle* "Really?" asked BMO.
*Ping*
"Oh my, I had no idea," said BMO.
*Ping*
"Indeed," said BMO before facing Finn and ask, "Finn, who is your charming friend over here?"
"That's Mother Box or MB, she has been my companion in my journey through the megaverse, I would have gone mad centuries ago if wasn't for her," said Finn and the others looked at him strangely. Noticing the looks he asked, "Yeah, it's a long story. Can we go somewhere more comfortable?"
"Ok, I think it's better if we go to the tree house," said Jake.
"Before we go two things. First," he made a few hand motions drawing runes and sigils in the air, they floated to Phoebe and circled her before disappearing.
"And second," said Finn before pulling FP in a hug and kissed her. At first she struggled to get away from him in fear of burning him even if she had a fire shield on her, but then she felt the soft skin of his lips pressing against hers followed by his tongue entering her mouth, as his tongue explored the interior of her mouth she moaned in pleasure, this was the first time in her entire life that she felt soft human skin without burning it, plus the kiss was overwhelming to her.
FP's legs gave out under her, but Finn held her against his body as he deepened the kiss and after a few seconds he pulled back leaving FP in a daze. She unconsciously laid her head on his chest and closed her eyes.
"I always wanted to know what was like kissing you without burning," said Finn after pulling back and the princess still dazed just nodded. While FP seemed lost in her own little world and kept drawing small circles on his chest using her finger Finn called, "Hello, Phoebe, hello, Ooo to Phoebe."
Rolling his eyes Finn just picked her up and carried her, bridal style, to the tree house. The other three just looked shocked that Finn, the shy and awkward kid, just kissed a girl, made her weak on the knees and just carried her like a blushing bride, Jake kinda felt pride for his little bro. Marceline and Bonnie felt jealous and they kinda wanted to be the ones to be kissed and carried by the hero, although Marceline scenario was far more risqué and kinky than Bonnie's.
Few minutes later in the tree house
Phoebe recovered from the experience when Finn set her on the sofa, her face literally brighten with the embarrassment but then she tried to focus on the feeling of the soft cushion she was sitting on.
"What happened back there?" asked FP.
"I just used a spell that allow you to interact with the world around you in a non-elemental manner, pretty useful don't you think?" asked Finn after his explanation.
"Very," said Phoebe licking her lips and almost losing herself in the memory of what happened, it was this moment that the other three arrived.
Jake just moved to sit on his chair with BMO sitting on the table, just like old times. Marceline and Bonnibel glared at Phoebe as soon as they saw her, she just gave them a smug look, she had no shame in admitting that she enjoyed her little trip to la-la-land. This little exchange was missed by Finn as he was looking around the house and was comparing it to his memories, after looking around he set on the sofa beside Phoebe.
"So, you probably have questions but wait until I finish my story, ok?" asked Finn and they all nodded. Then he started his long story detailing his journey across many worlds, "Ok, after I fell into the void…"
