Izure Saikyou no Renkinjutsushi? - Ch. 38

[MangaDex]

 

[freakofnature]

The translation stumbles a bit on page 9: it's true that 地獄耳 (jigokumimi) does literally translate as "hell-ears", but the actual, non-literal, meaning is "sharp-eared" or "good at gathering information or learning secrets".