A Christian fighting in a Crusade [1] and most recently 21st century Christian nationalists and alt-right groups [2]. Also recently being used quite a bit in the UK in relation to some anti-immigration movements.

[1] - https://en.wikipedia.org/wiki/Deus_vult

[2] - https://en.wikipedia.org/wiki/Deus_vult#Adoption_by_21st_cen...