It's called a Pyrose! Hawthorn and her father happened upon it one day, thinking it was a leftover from a Revenant raid. However when the rose failed to extinguish even under water or wind, they decided to bring it home and watch its progress from home. The only time the rose dimmed or faltered was when hope was at an all time low. The truth is the rose is a gift from Sarina to Hawthorn to encourage her to fight, the Pyrose will burn forever as long as there is hope. It is only truly ever hopeless when the fire dies.