This haiku from Clark Ashton Smith (CAS) was unpublished in his lifetime, and is not available on The Eldritch Dark, so here's the complete text:
He draws empyreal breath
Who buys no potion
From the pharmacy of death.
I believe the title of this poem comes from the Latin adjective meaning "enlightened", rather than having anything to do with the Bavarian Illuminati (or the many imitators that have sought to succeed them in the following centuries).
Given that context, these lines do express an unusually hopeful message to emerge from CAS' pen, since they suggest that the enlightened individual can, in some unspecified way, transcend the death of the physical being. CAS did cultivate an interest in Buddhist philosophy towards the end of his life, and I can only assume that this haiku was inspired by the same.