Here is the full list of all 33 Mitsurugi Kamui Hikae achievements. It takes around 8-10 hours to unlock all of the achievements on Windows.
Complete all upgrades
Clear Very Hard difficulty
Collect 100,000 SP
Clear Inferno difficulty
Clear Hard difficulty
Perform 10 Flourishes
Defeat 1000 enemies
Perform a Flourish
Clear Easy difficulty
Perform 10 Counters
Max out Katana Gauge
Clear Normal difficulty
Defeat stage 6 boss "Magatsu Hino Tsurugi" (any difficulty)
Perform 10 Just Guards
Defeat stage 3 boss "Suzuka" (any difficulty)
Defeat stage 4 boss "Magatsu Kaina" (any difficulty)
Defeat stage 5 boss "Magatsu Suzuka" (any difficulty)
Perform a Just Guard
Perform a Counter
Defeat stage 2 boss "Kaiser" (any difficulty)
Defeat 100 enemies
Use Zanshin to defeat 100 enemies
Max out Life Gauge
Defeat stage 1 boss "Kaina" (any difficulty)
Defeat 10 enemies
Use Zanshin to defeat an enemy
Use Zanshin to defeat 50 enemies
String 50 hits
String 100 hits
Perform the holy technique "Celestial Judgement"
Perform the holy technique "Divine Wind"
Reach "Mitsurugi" zeal level
Watch the tutorial