There are a maximum of 29 Aarklash: Legacy achievements worth 668
73 tracked gamers have this game, 6 have completed it (8.22%)
Start a new game in Rag'narok level of difficulty; then reach and kill Baron Mornstar without ever pausing the game. Make sure you disable the tutorial and the automatic pause options.
Unlocked by 10 tracked gamers (14% - TSA Ratio = 2.70)