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