Like all other characters, a normal ending will take place if the player does not invite enough guests to the party.At the party, Seven tells everyone about Yoosung's eye and that he wasn't going to come to the party. Everyone then rushes to the hospital. V is there and tells what happened to Yoosung. Then he tells player that he would like to see her alone. Everyone leaves and Yoosung wakes up. Then a CG of Yoosung lying on the hospital bed will appear. Yoosung will then tell player how much she means to him followed by a normal ending screen.
Bad Story Ending 1
If the player manages to convince Yoosung that they and Rika are alike and constantly takes his side, he eventually comes to strongly believe in this logic and appears to have confused the player with Rika, to the point where he says that the player 'almost feels like a reincarnation of Rika', much to the others' dismay.
On the 7th Day, when Seven reveals how he had noticed traces of a hacker in the security system at Rika's apartment around three days ago, he and Jaehee begin to question the player's safety as the former reveals that the system has been altered such that when members of the RFA visit Rika's apartment, or if the player leaves the apartment, a bomb installed in the apartment will detonate. Both instruct the player not to leave the apartment under any circumstances as Seven proceeds to fix the problem as fast as possible. Afterwards, in a subsequent chatroom, Yoosung anxiously asks the player if they are alright, and labels V as irresponsible for not being here in times of a crisis. He eventually resolves to get Rika's address out of Seven, and assures the player that he will come and save them.
At Seven's apartment, Yoosung asks for Rika's address, saying he can't lose the player like how he lost Rika. Seven tries to calm him down and says he will call V, but Yoosung threatens to destroy all his laptops if he does so. Yoosung reveals he '[can't] trust anyone in the RFA who can move on after losing Rika', and does not believe Seven's warnings in the chat history as a result, since he 'couldn't save Rika either'. He says that if he doesn't go and save the player, no one else will. Seven eventually yields and tells him to hold on as he goes to call V. While Seven is busy, Yoosung eventually deduces the GPS coordinates of Rika's apartment from a CCTV footage and proceeds to find the player. Seven eventually contacts the player through a chatroom, revealing Yoosung's disappearance from his apartment, and pleads for the player to text him if they ever see Yoosung.
When Yoosung arrives at Rika's apartment, he confirms their safety, while noting that the player looks completely different from Rika; from what he had imagined. He promises that he will protect the player and 'won't let you leave like Rika'. As he professes his love for the player, both are seemingly caught up in the bomb exploding in response to Yoosung's presence as a RFA member as the background turns white, before the bad end screen appears.
Bad Story Ending 2
If the player constantly takes Yoosung's side and agree with him that V is not trustworthy, especially due to the events of the hacker incident, Yoosung will eventually ask the player to come out and meet him at Forest Park 246 to tell them something very important on the night of the 8th Day, after the hacker incident has been resolved. Jumin and Jaehee, however, are not completely convinced and agrees that they should send a couple bodyguards to keep watch just in case. Jumin mentions that he has a bad feeling, before he proceeds to try and reach V.
When the player meets Yoosung at the park, Yoosung is happy to see them despite meeting face-to-face for the very first time. He then reveals that he wants the player to leave RFA with him due to him not being able to trust V anymore after the preceding events that occurred, and finds his behaviour highly suspicious. As he requests this, the voice of an unknown person catches their attention as he is caught by someone from the RFA - presumably one of Jumin's bodyguards - and the pair learns that this same person is somehow involved with the RFA. As Yoosung decides to go closer, the unknown person cries for help, saying he '[doesn't] want to die like her'. This spurs Yoosung forward in offering a helping hand to the stranger.
The stranger says that he was supposed to keep mun about an autopsy he had done on the body of a murder case as he was enticed by the promising offer of being paid handsomely. This leads to Yoosung believing that Rika's death was not suicide, but murder instead. The stranger seems to fear for his own safety, continuously questioning Yoosung if he, as a RFA member, was trying to make him spill the beans and that people around him would get hurt by the organisation since he was told a hacker would always be watching him. Yoosung proceeds to break his own phone and offers to be searched by the stranger, if it means being able to know the real truth behind Rika's death. The stranger then complies; only on the condition that both Yoosung and the player take him somewhere that can make him feel safe, as he notes that his car is just nearby.
Once in the car, the stranger reminds Yoosung that they would have to protect him, to which Yoosung replies without doubt, saying that 'if everyone realises that V tricked them too, they'll all help [Yoosung and company]'. The player, however, notes that the situation is a bit strange. When Yoosung questions the player, the stranger asks if something happened again and calls out Yoosung's name, saying he can't be responsible for anything that happens. As the player and Yoosung begin to question how the stranger knows Yoosung's name without having been told yet, a muffled cry comes from Yoosung as he is knocked unconscious. It is assumed that the player undergoes the same fate shortly afterwards.
The stranger notes that Yoosung is a precious hostage until he is brought to Magenta, and reveals what he has said earlier on was all a ruse to trick Yoosung into trusting him, and that he is indeed the user Unknown who has contacted the player in the prologue of the game. He mentions that although the player has ruined his plans, he will re-educate them, and be together at 'Magenta, the place of hopes and dreams'; the place where he claims to be paradise. The bad end screen then appears.
Bad Story Ending 3
If the player panics about her safety and convinces Yoosung to protect her at all costs, Yoosung decides to help Seven infiltrate Mint Eye's base on the 10th Day. During their investigation, they are caught by Unknown, who has a switch that will cause the bomb in Rika's apartment and the base to detonate, killing all four of them. Yoosung distracts Unknown by grabbing onto him, while Seven escapes with the switch. Furious, Unknown attacks him.
In a subsequent chatroom, Seven sadly announces that Yoosung has been left at the base, and he had escaped alone. However, if it means that the player will be safe, Yoosung does not mind sacrificing himself and never returning. When he wakes up, he finds Unknown taunting him and urging him to eat despite his lack of appetite. Unknown threatens him with the safety of the player and RFA if he falls unconscious, and entertains himself with torturing Yoosung. Amused, Unknown suggests the idea of tying Yoosung up and forcing him to stand for an entire day, just as his mother used to do with him.
Bad Relationship Endings
Bad Relationship Ending 1
If the player fails to get enough likability with Yoosung by the 7th Day, Yoosung confronts the player in a chatroom and requests that they don't feel offended by what he is about to say. He then reveals that he might have confused you with Rika, which misled him into thinking he had romantic feelings for you. Yoosung expresses his remorse, saying that he is not ready to be in a relationship yet, before leaving the chatroom to hang out at Seven's place afterwards.
In a subsequent visual novel sequence, Yoosung and Seven have a friendly argument of whether Yoosung deserves to eat Honey Buddha Chips after achieving victory in LOLOL. Yoosung asks if he could live with Seven, in which the latter answers with a no. The background then fades into black, with Seven breaking the fourth wall and explaining to the player that the game will end here for not having enough likability points. He requests for the player to not hate them and please play again, before the bad ending screen appears.
Bad Relationship Ending 2
If the player fails to get enough likability with Yoosung by the 10th Day, Seven makes Yoosung wait outside when they investigate Mint Eye's base. Seven is approached by Unknown, who threatens him with a switch that will detonate the bomb in Rika's apartment. Seven begs for her life, and Unknown is excited at having him at his mercy.
Outside, Yoosung notices that Seven is not coming out, and he begins to worry that he is not strong enough to protect the player like he had wanted. Since the only thing he is good at is playing video games, he feels that he can't help during times of danger and scolds himself for believing just this once that he is able to do something useful. Without the player encouraging him, he becomes unconfident. Suddenly, he realizes something is wrong, and back at Rika's apartment, the bomb sets off.
If the player has attained enough hearts and invited enough guests to the party, the good ending will take place.
As Jaehee, Zen and Jumin finally meet the player face-to-face at the entrance, they begin to wonder if Yoosung would be arriving with V. When the four of them go inside, they meet Seven, who begins to degrade himself as 'a moron, an imbecile, and twitchy' as he starts to tear up. He reveals that while they were at the hideout, Yoosung was injured by the hacker in his left eye and might even go blind. Jumin notes that V knows about this as he had given him the contact details of an ophthalmologist the day before, believing that V was finally seeking treatment for himself. Seven continues to blame himself despite Jumin reassuring him that it was not his fault that Yoosung got hurt.
Just as the RFA members conclude that Yoosung and V would not be appearing at the party and decide to make a trip to the hospital afterwards, they hear V welcoming all the guests to the party. V makes a brief speech about the history of RFA, before introducing Yoosung to the rest of the party. The other RFA members are left shocked at Yoosung's unexpected appearance at the party, and notices the bandages over his left eye. As Yoosung begins his speech, noting how he is able to see guests with his remaining right eye, and being finally able to see the player, the RFA members decide to bring him to the hospital to get his eyes treated after the party.
Yoosung begins to talk about Rika, mentioning how she has made many people happy through her actions and how she had given him a purpose in life through her influence. He says how he had began to yearn for love after her passing, and had even considered the player's love for him as the same as Rika's, but learnt that he should never compare the player's love to anything else through the rest of the RFA members. Yoosung then directly addresses the player, telling them to not worry about his injury and how glad he is to be able to sacrifice himself for them. He promises that he will cherish them more, and always become better for them so that they would never regret being with him. He concludes his speech by noting how RFA was founded by everyone's love for each other and the sharing of values, and requests for everyone to continue doing so, before he steps down from the stage and heads towards the player.
As Zen notices how Yoosung is getting too close, Yoosung says that he wanted to see the player so much, before kissing the player, noting once more how the player is not Rika. The credits roll, and the good ending screen appears.
Yoosung is now a veterinarian and is married to MC. The player enters his office and puts new glasses on him. The CG shows that Yoosung is visibly blind in his left eye. Yoosung pouts and asks if she's already tired of his glasses. He says he doesn't need new ones since his eye surgery is on Friday. He laughs after the player says that she likes people that wear glasses. Yoosung then says that he can't wait to see her with both eyes, since she's already pretty now, so she'll be twice as pretty when seen with both eyes. He goes on and says some cheesy things. When the player says that he's making her cringe, he continues with the cheesy lines. The player tells him to stop and asks about the dinner menu. Yoosung whines and says that he was going to cook. He changes his mind and says that since there aren't many patients, they should go out and eat for once. Yoosung says that he likes eating at home, but going out to eat once in a while isn't bad. The player says he's being like a baby, to which Yoosung responds that they should have a baby soon to prove the player wrong. The player says he's being glib, and he agrees. He then asks, "Will you go out with your husband tonight?"