Tanner was a supporting character in The Elite and The Guard. He can be credited with saving Maxon and America's lives on the night of a Southern rebel attack in The Elite. While Maxon didn't get his name when Markson asked him, America was able to say he had a pewter ring on his thumb that helped identify him to Markson. Tanner was killed that night.
His pewter ring belonged to his grandfather, and it was so big that it would only fit on his thumb. His wife got on him about it, and he promised her when his service was up, he'd get nicer rings for both of them. Unfortunately, he couldn't do that to please his wife before he died.