Deriving from the ancient Greek words "hell" and "fat", hellafat has become a colloquialismexpression of seniority amongst Discord servers. It is a high ranking tag of an elite crew and demands respect.
hellafast is prettydamned quick. It's not as fast as stupidfast, but it'll still smoke things that are just "fast". e.g., ASDL is hellafast, compared to a 56K modem.