“Bleys” is another spelling of the name “Blaise.” According to Geoffrey of Monmouth, Merlin learned magic from his master Blaise. Bleys is a powerful sorcerer, like his other full-blooded siblings. Blaise is also the name of a Catholic saint who is the patron of throat injuries and ailments and of choking victims.
Then came a fiery bearded, flame-crowned man, dressed all in red and orange, mainly of silk stuff, and he held a sword in his right hand and a glass of wine in his left, and the devil himself danced behind his eyes, as blue as Flora’s, or Eric’s. His chin was slight, but the beard covered it. His sword was inlaid with an elaborate filigree of a golden color. He wore two huge rings on his right hand and one on his left: an emerald, a ruby, and a sapphire, respectively. This, I knew, was Bleys.- 9 Princes in Amber Ch. 3