Masachika was a young man with an average build and short, spiky black hair. He had noticeably small, rounded eyebrows and two prominent scars on his left cheek. His mouth was usually curved into a happy smile.
Not much is known about Masachika's personality, however, he was likely a very kind person, befriending Sanemi and even introducing him to someone that could help train him. In his will, Masachika considered Sanemi as a brother and wished the best for his loved ones.
After Sanemi began wandering in search of demons to kill, he met Masachika by chance. Masachika was already a member of the Demon Slayer Corps, and he arranged a trainer for Sanemi so he could properly learn how to defeat Demons. The two challenged and successfully defeated the previous Lower Rank 1 of the Twelve Kizuki, but Masachika perished in the conflict.
Sanemi rose to the position of Wind Hashira alone, bitter over his friend's death. When he confronts Kagaya Ubuyashiki about the latter's inability to fight, Kagaya apologizes for his weakness and identifies Masachika by name, much to Sanemi's surprise. Kanae Kocho then informs him that Kagaya has memorized every slain Demon Slayer's name and background, and Kagaya decides to give Sanemi Masachika's will.
Some years prior to the beginning of the story, Masachika encounters Sanemi by chance. They strike up an unlikely friendship, and Masachika even introduces Sanemi to a personal trainer so he could properly cultivate his skills. An unknown amount of time later, (but still several years prior to the beginning of the story) Masachika dies in battle against a past Lower Rank One.
Sanemi and Masachika had a close brotherly relationship, with Masachika viewing Sanemi as the younger brother he lost.
Overall Abilities: Masachika was an incredibly powerful swordsman in his own right, as a tag-team effort between him and Sanemi was able to successfully defeat Lower Rank One, the most powerful of the Lower Ranks despite sacrificing his life in the process.
- First Form: Dust Whirlwind Cutter (
壱ノ 型 鹿 旋 風・ 削ぎ Ichi no kata: Jin Senpū - Sogi?) - Masachika dashes forward and slashes in a horizontal cyclone pattern.
- Second Form: Claws, Purifying Wind (
弐ノ 型 爪 々・ 科 戸 風Ni no kata: Sōsō - Shinato Kaze?) - Masachika lifts his sword upwards towards the right, above his head and unleashes four vertical slashes down on the enemy like claws.
- Third Form: Clean Storm Wind Tree (
参ノ 型 晴 嵐 風 樹San no kata: Seiran Fūju?) - Masachika unleashes a whirlwind of slashes around his body that can defend them from incoming attacks and slice up their surroundings.
- Fourth Form: Rising Dust Storm (
肆ノ 型 昇 上 砂 塵 嵐Shi no kata: Shōjō Sajinran?) - Masachika creates several slashes above them from below their target.
- Fifth Form: Cold Mountain Wind (
伍ノ 型 木 枯らし 颪Go no kata: Kogarashi Oroshi?) - Masachika creates several circular arched slashes that increase in size from above their target.
- Sixth Form: Black Wind Mountain Mist (
陸ノ 型 黒 風 烟 嵐Roku no kata: Kokufū Enran?) - Masachika rotates his body in a uppercut movement, creating a tornado of slashes.
- Seventh Form: Gale, Sudden Gusts (
漆ノ 型 頸 風・ 天 狗 風Shichi no kata: Keifū - Tengu Kaze?) - Masachika leaps into the air while swinging his blade which generates gale-force winds to shred their opponent apart.
- Eighth Form: Primary Gale Slash (
捌ノ 型 初 烈 風 斬り Hachi no kata: Sho Rekkaza Kiri?) - Masachika leaps into the air and swings his blade which generates circular torrents of wind.
- Ninth Form: Idaten Typhoon (
玖ノ 型 韋 駄 天 台 風Ku no kata: Idaten Taifū?) - Masachika backflips into the air and while upside-down, unleashes a powerful gust of circular wind.