Dark green dragons, once they mature, appear to become an entirely different species. However, this isn’t true. Rather, they burrow underground and get nutrients from their vines. These vines are sometimes referred to as Dragon Grass. These dragons are very violent, and will use their vines to capture, kill, and eat anything that moves, as well as nearby plants. Luckily, their range is limited and they cannot use magic. Dark green dragons tend to be easy to spot since they usually kill all plants around them and thus are usually surrounded by a large clearing.

Dragons are highly-intelligent reptilian creatures that—from a human perspective, at least—appear to live forever. Many different varieties of dragon exist, each with their own unique qualities, habitats, and behavior. Adolescence in dragons is usually marked by the growth of a hatchling’s wings, although not all breeds of dragons grow wings and some breeds have other traits that indicate the beginning of maturation. In Galsreim, dragons and humans coexist peacefully.

Flourie seems to be a cold-hearted dragon, because she always stays far away from the others.  But if you get known to her, you'll find out that she isn't that cold as she wants others to believe, she just don't like their company. Of course she has the temperament as a dark green dragon should have, but if she wants to, she could be close to friendly. That could be because of her special friendship to the silver dragon Tender Mercy, who is the only dragon who can come close to Flourie without being attacked by her vines.