Troop HP: increase
Troop DEF: increase
Troop ATK: increase
Use her early to do campaign mode, upgrading her as necessary.
Devana is a class of hero that is a specific type but applies troop bonuses. She is similar to Chae Seoyun, except that her tactical skill is more powerful at +5 than Chae Seoyun, which makes her a better choice for wall defense than Chae Seoyun. In every other regard the two heroes are identical.
For this reason you should max her to 210 and stick her in your sanctuary troop formation. She is the only four star hero you should use in that formation.
At +5 she adds a Troop HP bonus, Troop DEF bonus, and Troop ATK bonus of +16%.
She can be obtained in Noah’s Tavern, or the Hero Survival Shop.