A Scarlet Night (緋の夜 Hi no Yoru?) is a natural phenomena that takes place every three years in Tales of Berseria. Both the Opening and the Advent take place on a Scarlet Night, ultimately setting the game's plot in motion.
When a Scarlet Night occurs, the moon becomes full and turns a crimson red, recoloring the sky and even the ground with its presence. As Eleanor Hume explains it, legend holds that the crimson moon is a "gate to the beyond, and is proof of humanity's sins". Eizen elaborates that a Scarlet Night occurs whenever a full moon reaches a certain position, causing the land and the moon to pull at each other, earthpulse energy spilling into the sky and turning it red. Such power has the potential to produce enough mana to affect even that of an Empyrean, making it an ideal time to conduct a ritual such as the Opening or the Advent. Due to humanity's sins, the earthpulse is stained with the blood of humans throughout history, which is in turn emptied into the sky, making the Scarlet Night a symbol of human sin. Humans are far more likely to fall prey to malevolence during a Scarlet Night, resulting them becoming daemons.
- In Tales of Zestiria, on the night when Sorey and his group hunt for a drake, the moon is pink-colored, likely a remnant of Scarlet Nights. In addition, a middle-aged woman in Pendrago's Shrinechurch reveals an "ancient prophecy" to Sorey that says: "When the sky runs red, the world will be shrouded in evil", likely referring to Scarlet Nights.
- In Tales of Zestiria the X, after Sorey wakes up from his dream in which he meets Velvet Crowe, the Scarlet Night is in full swing. Alisha Diphda and the others bury Lunarre, then depart for Mount Killaraus.