So underplayed is the language in this paragraph that the reader probably has to read it twice to take in its horror. Valerie is a child. Note the child-like way in which her age is spelled out and the casual reference to the Whistler, as if he is already stalking the land like a dark creature of legend.
Wyndham poses a puzzle that the reader, willing or not, feels compelled to explore. Do you see how he defers the punch-line, like a skilful comedian, with a succession of commas and seemingly irrelevant clauses across all of 43 words?
Indeed, this character - portrayed at once as ‘all black’ and a ‘bird of prey’ - is ‘very good on the blades’. He is an assassin. The sinister undertones are made all the more alarming by his incongruous description as ‘an elderly gentleman’.
From just these few words, the reader has grounds to suspect that the protagonist is a man of substance (Dmitri treats him deferently), that the story takes place in Eastern Europe (‘Dmitri’), and that something unpleasant is about to happen.