Use a hex atbash (0=F) to get

78 80 84 56 53 67 76 65 77 65 78 84 73 83 54 55 56 67 90

Convert decimal to Ascii

NPT85CLAMANTIS678CZ

Make a 4×4 grid

Read going down from the upper right C

cvv59crypto322je

Rot 13 gives

putneurgreatoldneeeixeejm

Let’s split into passocode format

put ne ur great old ne ee ix ee jm

Numbers are using the last two letters of their written form

put94 great old 1 363jm

Searching the keyword part in Google gives Cthulhu

put94cthulhu363jm