Greenblings

Soukanna is the family ship between Shin Tsukimi and Kanna Kizuchi from the Your Turn To Die fandom.

Canon
Shin Tsukimi (going by the name Sou Hiyori) initially takes advantage of Kanna's naivety to manipulate her into cooperating with his schemes. He eventually becomes fond of her and cares deeply for her well-being. Kanna is the only Death Game participant whose survival Shin prioritizes above his own.

In Chapter 2, Part 1, Sou manipulates Kanna into making a trade with Q-taro for Kai's laptop, by using her "sister's" cellphone as a bargaining chip. After Kanna takes the laptop, she heads to the Ruined Corridor, and is subsequently followed by Keiji and Sara, who are looking to take it back.

When Keiji asks if Kanna could come closer and talk to him and Sara, Sou appears and tells him that he doesn't approve of his flirting, making snide comment asking if the two of them were on a date and that he thought the location wasn't very exciting. Keiji points out that he could say the same to Sou (who was accompanied by Kanna), and Sou laughs and agrees.

In the end, Sou and Kanna trade the laptop for the phone, and Kanna reads the Sou's changed message for her:
 * Live, Kanna
 * Even on your own


 * Don't cry
 * I'm sorry we couldn't
 * go together


 * I love you,
 * Kanna

Upon reading the message, Kanna begins to cry, telling her sister that she loves her over and over again.

In Chapter 2, Part 2, if Alice survives, the survivor's discussion on the Long Stairs during their escape changes. Kanna asks Sou what his plans are for when he escapes and taken aback, he answers that he might go see a movie. Kanna cheerily replies that that sounds great, and that she wanted to come along with him. Alice, suspiciously listening into this conversation, asks Keiji if he shouldn't accompany them in case. When Keiji agrees, Kanna becomes even more excited and suggests that everyone should watch a movie together.

During the second main game, Shin believes Kanna has the Sacrifice card, and attempts to make her the only survivor by convincing everyone to vote for her execution. When she admits she isn't the Sacrifice, Shin struggles to deal with the aftermath. He despairs because his inevitable death is seemingly coming for him and that there's no way anyone wouldn't vote for him, but is shocked when Kanna volunteers to be voted for. Sou angrily insults Kanna's naivety, telling her that her death won't solve anything, and calls for everyone to vote him instead.

At the same time, Kanna insists on being the one to die. In her eyes, Sou would be more valuable for everyone else to escape, given his knowledge and hacking skills, and she judges that he is worth more alive than she is. This mirrors the same way she previously judged Sou to be worth more to the group compared to Kai.

Kanna Survives
Should the player vote for Shin, Kanna will be saddened by his death and hardens her resolve to live in order to not waste his sacrifice.

In Chapter 3, Part 1, it is revealed that Kanna realized that Kugie was not the person who wrote the cellphone message, and that she understood it was left by Sou, who was trying to encourage her in his own way.

Throughout the chapter, Kanna regrets not getting to know him better and seeks to learn more about him in every opportunity.

Shin Survives
Should the player vote for Kanna, Shin will become vengeful and vow to kill the kidnappers, the Floormasters, and everyone who voted for her.

In Chapter 3, Part 1, Sou pretends that his goal in helping Kanna was to use her Sacrifice role to escape with her. When Keiji coldly points out that Kanna would only have ever chosen Sara to escape with her, Sou painfully admits that he knew that already. He lashes out at the rest of the survivors, and only agrees on a temporary alliance for survival.

Official 4-komas
Official 4-komas exist as a series of comedic comic pages about the cast of YTTD.

In 4-koma Season 2: #18, Kanna looks through Sou's laptop in order to discover what he is thinking behind the scenes of the Game. She then sees his search history, which is comprised of various topics related to her, including searches of, "Junior High School Girl Bucket", "Bucket Hat Size", "Bucket Hat Beanie", "Why wear a bucket?", "Bucket Trend Junior High School", "Way of dealing with a younger girl", etc. Kanna is immediately surprised, and then blushes heavily in shock. She excitedly exclaims about how Sou might be crazy about her, but mumbles to herself in an afterthought that it would be scandalous for them to get together due to their age gap. As Kanna works herself up over the thought of them in a romantic relationship, Sou is seen in the background confused. The 4-koma artist joked about Kanna's heart going doki doki in a later personal tweet.

In 4-koma Season 2: #19, with a direct continuation off the previous 4-koma, Kanna talks with Keiji, admitting bashfully that because she believes Sou has a special interest in her, she's been growing romantically conscious in him as well, and that it's been getting harder to talk with him. Keiji confidently offers to help write her a letter to convey her feelings and Kanna beams as she responds in the affirmative. In the end, the letter Keiji writes for Kanna turns out to be an arrest warrant condemning Sou to a death penalty for kidnapping a minor, likely unbeknownst to Kanna herself. As Keiji's grip tightens, Sou shouts that there's a misunderstanding and that he's a victim and asking Keiji to call Kanna.

Fanon
Soukanna is one of the most popular YTTD ships. The age difference between the two (Kanna being in middle school and Shin being old enough to drink) is the main reason that the romantic Soukanna pairing is less common in the Western fandom compared to other ships and platonic Soukanna. In the Eastern fandom, Soukanna still remains a popular ship. Some shippers portray it as a one-sided crush on Kanna's side.

Fandom
FAN FICTION

PIXIV
 * ソウカン tag on Pixiv

Trivia

 * Soukanna has the third most fanworks out of any Your Turn to Die pairings on the Japanese site Pixiv, amounting to up to 103 works as of April 16th, 2021.
 * This is one of two pairs in Your Turn To Die where, depending on the player's choices, one of them dies and the other lives; with the other being Yabusame Siblings.
 * The two have been confirmed to be siblings in Chapter 3 Part 1.