So I search up Kanji in Sekiro since that font style looks similar to the one used in the game and I saw that you're right.

This kanji appears whenever an enemy attempts what's described as a "perilous attack", which is an incoming attack that can't be blocked by the player.

Unlike Sekiro himself, however, the shota doesn't appear to be adept at dodging or doing a mikiri counter, nor does he have a prosthetic shinobi arm with tools that would help him against would-be assailants.

This shota is in danger.

Danger.