Calbraith A.H. Rodgers, was a 22 year old pilot in the Royal Airforce. On May 3, 1942 he was shot down over a swamp in Germany. He had known what was coming, as he had a connection to the Green his whole life. He had become a pilot to escape the pull of the Green. When he went down and was about to die, the Green came for him and made him the Swamp Thing, protector of the Green. He served the Green until he took his place among the Parliament of Trees and hadn't moved until this day.
He left the Parliament to talk to Alec Holland. He warned Alec of Sethe and told him that the Parliament believed he was the one that could save the Green and stop Sethe. Because he left the Parliament, Swamp Thing died.