Caim is simply an merely a Gaelic rendering of biblical 'Cain', who appears in a variation of the fantastical pedigree of Dardanus that is spun out in Lebor Bretnach, the Middle Irish language recension of the compilation called Historia Brittonum (known in the 9th century version by Nennius). The Lebor Bretnach, greatly modifies the line, making emendations to earlier sources and tracing the line through Ham rather than Japheth with further spurious names: