She was Randall's wife, and always told him he belongs with his family, and should stop running off into the wild. When Randall ignored her and went on a hike, she died with the rest of the family without Randall when the bombs fell in 2077.
On October 29th, Randall strangely sent her a message even though he knew she was dead. The message described what happened during the air raid, and how she was right.
Char Clark is only mentioned in Honest Hearts.