鬼の

demon's

→ 鬼
phrase Rare #24,767
demon's の links 鬼 to a following noun, indicating possession or association; the exact translation depends on that noun.
JA: 鬼の力は強い。
EN: A demon's strength is great.

鬼の…急所!

The demon’s… weak spot!

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

伊之助この真下が鬼の顎だ

Inosuke, right beneath us is the demon’s jaw.

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

鬼の力がどんどん強力になってる急げ!

The demon’s powers are getting stronger and stronger. Hurry!

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

何だ今の…鬼の攻撃か?

What was that just now…? A demon’s attack?

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