A war casualty of a sort who died even younger than Butterworth: Georg Trakl, pushed over the edge by his experiences on the Carpathian front and dead shortly afterwards from a cocaine overdose:

http://publicdomainreview.org/2014/10/29/wild-heart-turning-white-georg-trakl-and-cocaine/

Butterworth was a great might-have-been: Trakl knew exactly what he wanted to do and achieved a much more significant body of work in an even shorter time, pointing towards the future in a way Butterworth didn't. Butterworth would been a lot easier to get on with, though.