Touch-the-Sky, aka Joe, was a Lakota war chief.
The companions first met him in South Dakota, where he and his people helped them (unintentionally) against Lars Hellstrom and his men. He later showed up in Amicus seeking their aid. He wanted to take over the valley of Ti-Ra'-Wa and use its power to cleanse the earth, but once the companions found out his true motives, Ryan killed him. (Demons of Eden)