の剣士

swordsman of

→ の

phrase Rare #41,117

swordsman of 剣士 means “swordsman” or “swordfighter”; の links it to the preceding name or noun, indicating association or possession.

JA: 彼は王国の剣士です。

EN: He is a swordsman of the kingdom.

Keith, the swordsman from Bringobull, has been training me well all this time.

We sent in several swordsmen, but...

— Demon Slayer -Kimetsu no Yaiba- The Movie: Mugen Train (2020)