This poem from Clark Ashton Smith (CAS) marks a strong return to the realm of the weird, a theme that he was not writing about so much in the early 1940's.
The speaker is one of the cursed offspring referred to in the poem's title: "I am that spawn of witch and demon". His mission is of ill intent, much like the incubus who fathered him:
I am that swart, unseen pursuer
Whose lust begets a changeling breed:
All women know me for their wooer:
Mine is the whisper the maidens heed
At twilight; mine the spells that lead
The matron to the nighted moor.
CAS takes things up a notch in the last stanza, where the cambion's designs go much further than simply propagating his wicked bloodline, as he seeks "To plot...The bale of realms, the planet's fall."
I can't help wondering if CAS considered submitting this poem for publication in Weird Tales magazine; although it never appeared in those pages, it seems like it would have been a natural fit for The Unique Magazine if he had sent it in.