Bartholomew "Bat" Lash is the son of Ezekiel Lemuel Lash and Martha Lash, who have both passed away. He is an extremely good gambler and also very good with the ladies.
Lash is caught cheating with a woman by her twin sister and somehow he ends up with both in bed with him. He was then caught by their father, who was very angry. Nine months later, one of the sisters is due on her pregnancy and her father believes Bat Lash is the father. He wanted to force Lash to marry her but Lash points out that they have switched places and that he had only bedded the other sister. He proved this by pointing out that Ellie bites her nails while Suzanne doesn't. Suzanne's baby starts coming and Lash helps her give birth while Suzanne admits that the baby is really Mike Stettler's, who had recently died after being kicked in the head by a horse. The sisters switched places since Lash would be able to provide for the baby. The preacher tells Bat Lash to leave town and he does.