JK was a good kid. He had his life great for 11 years until 'the incident'
JK is a JK who resembles a human boy ( he claimed that he's an evolved almost extict race of the humans, so his SOUL was clearly stronger than the rest, his soul is made of all the soul traits somehow ). He has dark purple spikey hair and purple eyes. He has fair skin and usually wears shades to act cool.
During snowdin, he wears a hoodie without hood, and later gel his hair and weared the ribbon like a bowtie before the papyrus date.
During waterfall, his hair lays lower, and wears a bandana. After papyrus called him, he changed his hair & outfit to the tutu ( which he dislikes ).
JK is a good JK. He cares for his brother JH (also V, too ).
He enjoys any undertale fan games and plans to create his own comic and game of undertale himself.
JK is quite lazy ( Sans trait), caring for his brother (Toriel trait ), brave to express his feeling (Papyrus trait ), determined to finish what task lies ahead of him (Undyne trait) and acts cool (maybe paps or MTT trait...? ) So in conclusion, UT has affected him, dramactically.
JK's immense determination grants the power to SAVE and heal at SAVE points. His SAVE file can be reloaded to repeat events that occur after it, but NPCs' memories are not completely erased unless a True Reset occurs.He can put things into his inventory & retain it even after a reset, which is way more powerfull and usefull than Frisk's inventory. This power emerged when JK first awoke in the Ruins.
He could take and/or keep a weapon and/or armour from his capsuled inventory (which has unlimited space ).
* to be added soon, ask JK for spoilers... *
Flowey attempts to kill JK after he pretends to offer honest advice ( though JK could dodge all the bullets but he fell asleep so he can't ) Toriel intervenes, fireballs Flowey, and serves as a guide to the Ruins. After the first puzzle, he encounters Chara's ghost/spirit, though does not reconize them at first. At the end of a long room, Toriel asks JK to wait for her to return and states that she has errands to do. To be safe, Toriel gives JK a cell phone to call her with.
JK travels through the remaining puzzles in the Ruins and eventually arrives at Toriel's home. He asks Toriel "how to exit the RUINS" several times which prompts Toriel to destroy the Ruins's exit. Toriel then battles him because she wants him to prove that he can survive outside of the Ruins.
Then, JK meets Sans and Papyrus in Snowdin Forest. The brothers set up traps and puzzles in an attempt to capture JK. Sometime between here JK finally know Chara's name. After passing through Snowdin, Papyrus battles JK.
Undyne, the head of the Royal Guard, pursues JK by shooting magical spears at him throughout Waterfall. Monster Kid often saves him from Undyne by accident because they are so excited to see Undyne in action. After a chase scene, Undyne destroys a bridge that he is standing on, and he falls into the garbage dump. Before he gets up, he recalls a memory from Chara's fall from the hole. In the garbage dump, Mad Dummy battles JK because he mistreated their cousin, Dummy, in the Ruins (though he did not). At the end of Waterfall, Undyne battles JK after she gives an abridged monologue atop a crag.
After entering Hotland, JK enters a lab and meets Alphys and Mettaton. Alphys tells him that she is not a bad guy, and Mettaton interrupts them with a quiz show. Alphys gives JK an upgraded cell phone after the quiz show concludes, and she says that she will guide him through Hotland and the CORE. Before his battle at the end of the CORE, Mettaton reveals that Alphys had created all of the traps in Hotland in an attempt to endear herself toJK. He then transforms into Mettaton EX and battles him.
While passing through New Home, the capital of the Underground, JK learns the story of Asgore and Toriel's children from passing monsters. Then, Sans judges JK in the final corridor and explains the meaning of LOVE and EXP. He also emphasizes JK's importance in the fate of the world.
JK enters the Throne Room and finds Asgore, who tries to make small talk, only to realize their fated confrontation. The two walk to the Barrier and Asgore gives JK one last opportunity to leave before fighting.
Just before the fight, Asgore shows the seven collected human SOULs, preparing the containment process after the battle. Right before the fight starts, Asgore destroys the MERCY button, making it impossible to spare or flee. However, at the fight's conclusion, JK explicitly choose to spare Asgore. After Asgore's talk about adopting him, Flowey appears, destroys Asgore's SOUL and takes the human SOULs. The game then abruptly closes.
After reopening the game, JK finds that Flowey has saved his own game over the SAVE file, having gained the power to do so with the 7 stolen human SOULs. Loading Flowey's game, JK confronts a powered up Flowey and defiantly steps forward, entering an initially hopeless battle with him.
After JK calls for help several times, the stolen SOULs begin to revolt: first, they heal him, and then they weaken Flowey, leaving him vulnerable to destruction. After reducing his HP to 0 and listening to his monologue, the SOULs remove Flowey's ability to SAVE or LOAD. After this, the SOULs leave JK and Flowey alone. At this point, he chose to spare a weakened Flowey before leaving the Underground, return to the surface, and end his journey.
After leaving the Underground, JK receives a call from Sans, who leaves a message about what happened to the Underground after Asgore died. This varies based on what monsters were killed and what friendships were completed.
JK gains Toriel's friendship by sparing her, but she does not make another appearance until the end of the route.
He wins Sans's friendship by sparing Papyrus, and can optionally hang out with him twice (once at Grillby's, once at the MTT Resort,)
He gains Papyrus's friendship by visiting him at his home and hanging out or dating him.
Napstablook can be befriended by smiling at them in the Ruins, and hanging out with them at their house.
If he chooses to give Undyne some cold water after being pursued, Undyne can be befriended. He visits Undyne with Papyrus's help, and Undyne gets "revenge" by trying to befriend him and become "besties", breaking her table, dirting her kitchen and setting her house on fire in the process. She tries to fight him to regain honor but realizes that he is a "wimpy loser with a big heart" just like Asgore and decides to be friends.
Mettaton can be befriended by sparing him, which can be done by getting his ratings to 144000 (100000 if his arms and legs have fallen off) in his battle at the end of the CORE.
Undyne, having been encouraged to send a love letter to Alphys, gives the letter to JK, who delivers it to Alphys. This results in a date sequence with Alphys in which she and Undyne realize their feelings for each other and Alphys begins to come to terms with her past mistakes.
After befriending Alphys, Papyrus recommends traveling to Alphys's lab. In the lab, there is a letter on the floor that, when picked up, reads a monologue and the instructions needed to proceed to learn "the truth." Walking through the bathroom door reveals an elevator which goes down to the True Lab after a malfunction.
JK proceeds to explore the True Lab and along the way learns of Alphys's failed experiments (amalgamates) with determination and also about the origin of Flowey. After exploring the True Lab and talking to Alphys, she gains the confidence to reveal the truth about her experiments to the rest of the Underground. While attempting to leave,he receives a phone call in the elevator from an unknown voice. The elevator immediately and forcibly brings him to New Home.
After returning to the throne room and confronting Asgore, again, the pre-fight dialogue is interrupted by Toriel, who stops Asgore from fighting JK. Toriel is immediately followed by the other main characters who encourage everyone to get along. However, in a surprise twist, Papyrus reveals that it was "a little flower" (AKA Flowey ) who told him to bring everyone there.
Immediately after this reveal, Flowey appears, having stolen the SOULs of the seven other humans. He attempts to kill JK, but Undyne, Toriel, Alphys, and Papyrus use their power to block Flowey's finishing blows. Directly after this, all of the Underground's monsters arrive to encourage him in the fight against Flowey. However, Flowey reveals that this has what he wanted all along so that he could absorb the souls of all the monsters in the Underground along with the seven human SOULs (AKA being way stronger than Photoshop Flowey ).
Due to the immense power gained from the seven human SOULs and all of the monster SOULs, Flowey transforms into his true form, and just before the fight begins it is revealed that he is actually Asriel Dreemurr.
After JK survived for long enough, Asriel transforms again. At this point, JK felt the souls of Toriel, Asgore, Alphys, Undyne, Papyrus, and Sans within Asriel and he started to freeing everyone's souls. HE restored the memory of each lost soul after repeating the events the said lost soul of a chosen character.
After saving each monster, JK realizes that there is still one more person to save. After choosing to save "someone else," Asriel's memories of Chara began to play in a slideshow style. It is then revealed this "someone else" is Asriel himself. After this, Asriel starts to feel the love the monsters feel for Frisk through the souls he has absorbed, and blasts him with his ultimate blast. But JK, overfilled with Determination transformed into his so-called 'DETERMINATIONIST' form and reflects the blast, while Asriel slowly loses the will to fight as he is overcome with his fear of dying alone.
After reverting to his child form, he apologizes for hurting everybody, and he
chose to forgive Asriel. Asriel destroys the barrier using the power of all of the SOULs before releasing them. Knowing that he will turn back to a flower without the power of the SOULs to sustain him, Asriel says one last goodbye to JK before leaving. He hugs Asriel before leaving him.
After the scene with Asriel finishes, JK wakes up in front of Toriel, Sans, Papyrus, Undyne, Alphys and Asgore. While the monsters remember little about Flowey and nothing about his incarnation as Asriel. At this point, JK backtracks through the Underground and talk to the other monsters one last time, before returning to the surface.
Backtracking to the very first room in Undertale reveals that Asriel is tending to the flowers. Asriel asks about JK's desire to travel up Mt. Ebott in the first place. Receiving no answer as he's embarresed to tell him, Asriel lists off foolishness or fate as possible motives, but comes to the conclusion that "only you (JK) know the answer."
After passing through the final door to the surface, JK leaves the Underground with friends. Asgore offers JK the chance to be the monsters' ambassador to the humans. Most of the main monster cast then leave one by one, except for Toriel, who asks about his plans. And at this point, JK chose to stay with Toriel and invite his bro.
After choosing to stay with Toriel, Season 2's finale shows Toriel bringing a slice of pie to JKs bedroom.
The Genocidal path of destruction
After visiting everything and doing some TRUE RESETS, JK got bored and started to think "What if I started to kill? What if I did a genocide route?.... Yea...Let's see how strong Sans really is...." And that started the genocide route.
Geno - Overall
While traversing the Genocide Route, many characters comment on JK's creepy smile. Sans comments that it would be great if he continued pretending to be a human, and Asgore inquires what kind of monster he is.
At the end of the Ruins and when going through New Home, Flowey determines that he is empty inside, just like himself. He concludes that the protagonist is Chara, and informs him of a plan he has to become omnipotent.
The only instance in the game where Chara makes an in-person physical appearance is at the end of the Genocide Route. They appear as an overworld sprite and speak into the fourth wall. Chara could be speaking directly to the player in this sequence.
After this appearance, Chara reveals that JK's "human soul" and "determination" were the cause of their reincarnation and that the merciless events that occurred during the route lead Chara to realize that the purpose of their awakening was power itself. Chara states they are the embodiment of the feeling received whenever STATS increase and proposes erasing the world and moving on to the next.
JK is given the choices to "ERASE" the world, or "DO NOT." Both choices lead to the same result.
JK chooses to "ERASE" and accompanied with a maniacal laughter, Chara calls the him "a great partner." Additionally, their eyes widen, and Chara
says to him that they will be "together forever." (
OH HELL NOT CHARISK ).
Now,JK is stuck in an infinite black abyss accompanied by a sound similar to howling wind.JK regrets for everything and starts to cry and hoping for Chara to give him a chance to go back. After 10 minutes, Chara speaks to him, knowing that he wants to go back to the world, and reminds him that his actions caused the world's destruction. After asking him if he thinks he is above consequences, Chara offers to restore the world in exchange for something, later revealed to be his SOUL. JK agreed to give his SOUL to Chara.
But... after Chara received JK's soul, he quickly shoves them and his soul into its original position, bring them into it and therefore ' banishing' them into his soul. He then used his power to bring back the world and do another TRUE RESET, this time to stop messing around with resets and give them a happy ending just like everyone wanted.