Cyprian May is a senior partner for the law firm Landry, May, Patterson, alongside Tony Landry. He is married to Ursula May (nee Chillingham), who is the sister of Tansy Bestigui, a possible prime witness in the Lula Landry case.
We see “the tall, thin, besuited man of around sixty” when he shows up at Cipriani (Cyprian in Cipriani, what are the chances?!), a fancy restaurant where Cormoran interviews Tansy Bestigui in the company of Ursula May and John Bristow. The “silver-haired and distinguished-looking” Cyprian has “a certain chilliness about his pale blue eyes” when he strides up to the table, surprising his wife and sister-in-law and summarily escorting them out of the restaurant.