Yugi Tsukasa/Relationships

Yugi Amane
Tsukasa is Hanako's younger twin brother and the person he killed.

While Hanako feels considerable guilt over killing him, Tsukasa however, doesn't seem to bear any ill will towards his brother for it, though he doesn't hesitate to use it as leverage to manipulate the latter. Whenever he encounters Tsukasa, Hanako becomes overwhelmed and has been shown to cry when Tsukasa begins to remind him of the murder he committed, Tsukasa knows he can make Hanako vulnerable easily. He's always eager to meet up with Hanako, greeting him with huge smiles and hugs. He tells Hanako he loves him and asks to play together just like they used to. They have both been shown to react negatively to others interrupting their reunions.

The twins seem to have been close since they were young and often did activities together, such as watching TV and going to festivals. They are shown to be holding hands in a commemorative photo taken upon entering junior high.

As supernaturals, Hanako and Tsukasa have opposing beliefs - Hanako maintains the correct relationships between humans and supernaturals, while Tsukasa thinks they should just be however they want. In a conversation with Nene, Tsukasa describes themselves as being polar opposites and compares their current relationship to that of rivals or arch-nemeses.

When alive and younger, Tsukasa used to bring gifts to Amane when he was sick. He cared quite a lot about his brother and seemed shocked when he found out that Amane was going to die.

When Amane miraculously got better on the twins 4th birthday, Tsukasa knocks his brother over and asks him if Amane loves him, which he responds to  smiling brightly "Of course I do!".

It is later revealed that Tsukasa made a wish for Amane to get better. The wish requires a sacrifice, which Tsukasa offers up as himself, showing just how much he loves his brother. However, that would be the last act of genuine love Tsukasa would give, and following his merger with the Entity inside the Red House, his "love" for Hanako would reach a more sadistic turn, leading to who he is in the present.

in Chapter 105, Yugi Tsukasa's manipulation of Hanako's emotions reaches its point of no return when following an incident that destroyed the Big Clock at The Sealed Auditorium and stopped Hanako and Yashiro Nene in time while keeping their consciousness awake, he approached Yashiro, kissed her, and took her away. This causes Hanako to internally get angry, causing his body to shake and shed tears in spite of the Time Stop.

Nanamine Sakura
Sakura made a contract with Tsukasa and has become bound to him; similar to Nene with Hanako. She treats him like a little child and would become exasperated if he does anything unnecessarily cruel. Despite this, she cannot disobey his wishes and still aids him in altering the supernatural's rumors. She acts as his assistant, broadcasting his altered rumors to the student body.

When conversing with Nene about him, Sakura says that Tsukasa never listens to her, his actions make no sense, and he has no sense of personal space. This is then shown by Tsukasa jumping onto Sakura excitedly in an uncomfortably close hug.

She then says that there is nothing she can do about it and that she decided to think of him more as a cat than a person. Tsukasa seems to hold some respect for Sakura and will alter his actions to a certain degree once reprimanded by her.

Hyuuga Natsuhiko
The two of them don't get along well except when it comes to following Sakura's commands or having to work together (eg. In the Tea Party Arc where Natsuhiko asks Nene out before Tsukasa dumps water on her from behind). Natsuhiko advises Tsukasa to be more gentle to girls, just as Sakura asked of Tsukasa as well.

Mitsuba Sousuke
Sometime after his death, Mitsuba made a wish to Tsukasa to not be forgotten by people, however, the wish was too unclear for him to be able to make anything but a weak supernatural form for Mitsuba, which he then used to haunt the school lockers in order to speak to his schoolmates.

After Mitsuba's real wish was drawn out thanks to his involvement with Kou, Tsukasa took advantage of the vagueness of the wish and twisted the rumors about him, turning him into "The Bent-Neck Boy at the School Entrance". This altered, monstrous form is more powerful but has also lost the humanity that Mitsuba once had.

In the Mirror Hell Arc, it was revealed that Tsukasa had created Mitsuba using an amalgamation of body parts he found as well as part of his original soul. This newly formed "Mitsuba" has the same personality but does not retain any of the original's memory. Tsukasa then gifted him with a brand new scarf that is dark red in color. Tsukasa appeared later to save Mitsuba when he was in danger from Number 3. He also pressured Mitsuba into consuming Number 3's heart in order to gain power, trying to force it down his throat at one point when the latter refused. He seems to view Mitsuba's new power with child-like fascination, attempting to rope him into fighting Hanako three times. However, in Mitsuba's fear of knives, he attempted to sneak away and refused to fight with Hanako.

Mitsuba is a vulnerable person and Tsukasa took advantage of that all throughout their scenes together, manipulating Mitsuba into being forced to trust him, distancing Mitsuba from Kou so that Kou would not be able to remind Mitsuba of their time they spent together with the gardening photos, and gave Mitsuba an illusion of choice. Mitsuba wanted to be alive so badly, and he thought that Tsukasa was the only way to do it.

Yashiro Nene
It is unsure of what Tsukasa actually thinks of Nene, but more so, she's an obstacle against his goals. In the Tea Party arc where they kidnap Nene and drown her within the boundary, their relationship can be described as minor teasing when Tsukasa pretends to eat her in fish form or makes advances when she says she hasn't kissed Amane. However, in the Hell of Mirrors arc, when Nene attempted to stop Tsukasa from forcing Mitsuba to eat No.3's heart, he nearly forces her onto the floor before picking her up, apologizing and saying that Sakura had told him to treat ladies nicely, and using his ability to press two fingers to her forehead and sending her off to sleep.

Throughout the Manga's story, Tsukasa has interacted with Yashiro a few times, all of them with the purpose of causing something that has something to do with Hanako.

In Chapter 105, he kisses Yashiro on the lips, and then takes her away, claiming that she's his new assistant. This leads Hanako's consciousness to flare up in anger, evident by his body shaking and crying despite the effects of the Time Stop.