Suga Koutarou (須賀 Suga) is a main character in the game Kirisame ga Furu Mori.
Suga is a young adolescent male, presumed to be around the age of 19 or 20, with raven-black hair and dark eyes. He is depicted to be wearing a black long-sleeved, sweater shirt and black jeans or dress-pants, much like a Gakuran, and a pair of formal shoes. He is a manager at a museum, and may often be seen with a sword. Later in the game, Shiori notices a light blue glow around the sword and concludes that Suga made the sword with night glowstone. He's also very tall.
Suga is described as gentle, but strange. At first, he gave off a rather menacing impression, given his slightly aggressive nature when encountering Shiori. He is however, very strict when it comes to rules, but even he won't obey them entirely, as seen when he runs into the forest again despite his past connection with it. He appears to carry some degree of swordsman skills, seeing as he was able to slice up the children sprite that were taunting him with little to no ease, aside from his degrading sanity.
He is revealed to be a rather sensitive man, as seen when the children taunt him, and when Shiori calls him by his childhood nickname after so long, and is even labeled as a crybaby. Suga is also mute, because of his past encounter with Kotori Obake, as he gave it up in exchange for Shiori's life. He only communicates through writing in memos, they are usually of few words because of the canvas size. And he has a bit of a straightforward nature because of it.
Suga is also capable of crafting accessories, as he made the night glowstone necklace for Shiori, and even made a sword out of the same material. Which explains why he was able to kill the children spirits with it.
Shiori and Suga have a very complicated relationship in the terms of balancing out whether they're incredibly good friends or possibly even more, though the ending allows the player to decide. Suga is shown to hold very passionate feelings towards Shiori, becoming forceful and attempting to remove her out of harm through getting her out of the museum, but when it's revealed Shiori is the owner of the mansion by legal rights, he opens up all of the rooms to her, and even follows her into the forest despite his past connecting with it.
When Shiori awakes from her flashbacks to her childhood, Suga is shown crying over her body, and even more so when she calls him by his childhood nickname. His personal feelings towards Shiori aren't entirely described, but are proven when, in multiple bad endings, he ventures out on a suicide mission against the Kotori Obake to buy time for Shiori to escape. In the true end, he calls her by her childhood nickname and says in a memo that 'there's a lot he'd like to talk about.'
Sakuma and Suga quite possibly might be at odds since she often hides out in the museum overnight and seems to be very dismissive of his constant annoyance with this. In Shiori's first encounter with Sakuma, Sakuma advises her to hide from the security guard, showing that she might be afraid of Suga in some sort of way. This may be because she was simply trespassing and didn't wish to be caught. She comments that Suga is "helplessly incomprehensible".
Officer Mochizuki and Suga seem to be on relatively good terms, as shown by the fact that Mochizuki adresses him as ''Suga-kun'', as opposed to Suga-san.