Cosmo Lengro

In the novel Lando, we learn that this is the real name of the Tinker, that mysterious character that appears in several of the Sackett stories. He is described as being a gypsy, which is a name for the Romani people, who originated in northwestern India about 1500 years ago. Accordingly, they tend to have a swarthy coloration with dark eyes and a generally exotic and mysterious look. All of that fits in with the character of the Tinker.