Sheen evolves from Chansin when fused with a Legendary Blade.
Sheen has eyes with light yellow sclera and blue slit pupils, and wears a large kasa hat with several small red thin beads hanging within the edges and a small orange wisp atop, a big cerulean blue scarf with ragged edges at the end that covers his mouth, a white top with two long cloth ends at front and back, a black hakama, and zori sandals with socks. He also wears wrappings on both arms and wields the Legendary Blade, which has a light yellow hilt with the same wrappings.
The item can be obtained as a reward from [Request #97] "Precious Illusion", given by the man on the Bamboo Path in Blossom Heights, starting from Chapter 11 after unlocking Rank B. After taking the request, defeat Benkei within the Old Mansion to obtain the Illusion Blade and return it to the man, who will let you choose your reward between a Legendary Blade and a Cursed Blade.
After clearing the request, more of the same item can be purchased at Jungle Hunter in exchange for 2 Sawtooth Stag (Rare) x2 and 3 Snakehead (Rare).
Alternatively, he can also be freed from the Crank-a-kai with a Five-Star Coin.
Fuse Chansin with the Legendary Blade. To get the Legendary Blade, fuse the Battered Blade (which can be bought at Jungle Hunter) with the Rough Whetstone (which can be gotten in the main story or through the lottery).
"Masamune" is derived from the legendary swordsmith (see Trivia). "Sheen" is a word meaning "a soft luster".
In German, "Schimma" is a corruption of Schimmer, meaning "sheen".
Sheen's Japanese name, Masamune, refers to Gorou Nyuudo Masamune, a swordsmith of the late Kamakura period, acclaimed as the greatest in Japan's history and mentor to many great swordsmiths. He crafted extraordinarily beautiful blades of high quality, in spite of how scarcely available pure steel was at the time: in particular he had perfected the art of nie, a method of embedding hard steel crystals in the forged blade, creating a finish that resembled a starry night sky. Contrasting with the legends around Muramasa Senji's blades (see Snee#Trivia), Masamune's swords were said to have a pious, even gentle soul to them, and would only cut what their master willed them to without taking lives indiscriminately.
One legend claims the two competed to see who could craft the finest katana: when both their swords were hung over a river facing the current, Muramasa's blade sliced all fish and dead leaves that floated through it, while they glided gently around Masamune's. The judge deemed Muramasa's sword technically perfect, but cursed and bloodthirsty, while Masamune's was a true weapon of justice, and for that reason he was declared the winner.