Because licensing Trajan Pro for a tattoo is free (you don't pay Adobe to tattoo yourself), many artists simply use Trajan. However, several dedicated "John Wick" fonts have popped up on free font websites:
Based on forensic typography analysis (comparing the serifs, the crossbar of the 'A', and the tail of the 'R'), the closest commercial match is: john wick tattoo font
Traditional and highly ornamental, featuring the sharp edges and heavy strokes seen on Wick's back. Because licensing Trajan Pro for a tattoo is