The Setaceous Hebrew Character (Xestia c-nigrum) is easily identified by the black mark on the wings which is thought to look like the letter nun (נ) from the Hebrew alphabet.
The same markings however, are on the very similar Hebrew Character (Orthosia gothica).
The Hebrew Character however, is much smaller and flies earlier in the year, during March and April while the Setaceous Hebrew Character flies from May untill November.

Caught in my self made moth trap.

In my yard, Hilversum, The Netherlands, 13 & 15 August 2018