Well, 'A Murder of Crows' is a must - read. It shows the complex relationship between Swamp Thing and the creatures in the swamp. Also, 'Down Among the Dead Men' is really good. It dives deep into the horror aspects of the Swamp Thing world, with great art and a chilling story.
Swamp Thing started as Alec Holland. He was a brilliant scientist with a goal to create a formula for bio - restoration. His work took place in a swamp. Unfortunately, bad guys came and things went horribly wrong. The lab burned and Holland, covered in his formula, fell into the swamp. And boom! He became Swamp Thing. He could now interact with plants in ways no one else could. His body was made of plants and he had a connection to the swamp that was really strong.
One key feature is its unique art style. The illustrations in 'Swamp Thing Graphic Novel' are often dark and moody, which really sets the tone for the story. Another feature is its complex characters. Swamp Thing himself is a very deep and multi - faceted character. Also, the themes explored, like environmentalism and the relationship between man and nature, are quite thought - provoking.
The main character is, of course, Swamp Thing. He is a creature of the swamp with a complex backstory. Another important character is Abigail Arcane. She has a connection to Swamp Thing and plays a significant role in his story. There's also Alec Holland, who has a relation to Swamp Thing's origin.