|First Appearance||Chapter 36|
|Last Appearance||Chapter 202|
|Status||Smiling Face Ltd. right-hand man|
|Known Relatives||Hisanori Hayasaka (older brother)|
Yukinori Hayasaka (早坂 幸宜 Hayasaka Yukinori) is the younger of the two Hayasaka Brothers and is a manga-only character. Part of his name, Yuki, is pronounced the same as the kanji for ice in Japanese.
Yukinori, or usually known as Yuki, is the younger brother of Hisanori Hayasaka. He is very loyal to his older brother but doesn't completely understand how his brother thinks. Yukinori and Hisanori lived in a cold and poor town in the past and were abandoned by their parents a long time ago. Yuki swore to follow his brother no matter what after Hisanori saved him from being buried alive under an avalanche. Yuki joined Hisanori in the blackmarket some time after that.
Yuki wore a thick fur coat in his first appearance as it was used to hide his weapons, the fish hooks. He removes it later as he had gained a "new power". Yuki appears to have developed a small rivalry with Godai after his defeat, wanting to fight him again in his second appearance, though Hisanori stops him before he could do anything. Yuki's favourite food is ice cream and his enjoys snowstorms.
Yukinori is a skilled fighter and uses glass fishing hooks in his fur coat as his weapons. He attaches the fish hooks in his pockets and swings them at the enemy to cut. The technique can be very dangerous as the translucency of the glass hooks can make the attacks seem to come out of nowhere. This technique has a weakness however. Yuki is left defenseless if both his hands are held and the opponent can easily attack him.
Later in the series he removes his furcoat and claims he had gained a "new power". It hasn't been shown in action, but during his encounter with Kasai, Kasai reveals the gloves Yuki wear hide gunpowder which explode when used to punch.
Shortly after the Onsen murder, Godai, who was left in charge of Yako and Neuro's office is visited by Yuki and his subordinates. Godai easily beats up the subordinates, but Yuki makes quick work out of him almost immediately. He leaves the office, leaving Godai feeling angry and unappreciated. Soon, Yuki is among the people seen during Neuro and Yako's first meeting with Tateo Mochizuki. He attempts to intimidate Neuro but becomes the intimidated when he unknowingly provokes Neuro. He later asks Hisanori to get him more reliable subordinates, as his current ones could easily be defeated by a former mob member. Hisanori complies, and Godai is recruited.
Later after Yako and Neuro were framed to get busted at the docks for drug trafficking, Yuki and Hisanori arrive to go through with their intended plans (Mochizuki had just planned for Yako and Neuro to be framed, the Hayasaka Brothers planned to take down both Mochizuki and Yako to take over the company). They bring Godai along to help capture Yako and Neuro, but Godai doublecrosses them at the last moment to rejoin the detectives' side. Yuki and Hisanori escape the debris Godai had piled on them and Yuki decides to fight Godai one-on-one while Hisanori deals with the others. After a brief fight Godai defeats Yuki while Neuro outsmarts Hisanori. Hisanori shoots his rocket launcher at the building to bring it down when he realised he had lost. Yuki, noticing this immediately goes over to help his brother out.
Yuki and his brother appear again during the HAL arc, where they supply Neuro with the helicopter to fly to the H. Ostwald nuclear ship. The helicopter wasn't cheap however, and Yako was left with a great debt after the HAL arc. She consults the Hayasaka Brothers on ways to earn cash quick, but their techniques weren't the type she would go through with (prostitution and illegal organ marketing). Much later in the series Yuki encounters Kasai in the back alley. Kasai easily identifies the type of weaponry Yuki was using and uses it against him to give him a serious injury. Yuki survives and returns alongside Hisanori after Hisanori avenged him by blasting Kasai's partner.
- Yukinori's gunpowder glove is very similar to Guren Kaina, one of Shishio Makoto's attacks from Rurouni Kenshin, as both involve filling a glove or gauntlet with gunpowder as a weapon. Also worth noting is that both characters have had this weapon backfire against themselves.