Spirit Mod 1.3.1 served to rebalance and expand upon every boss, added a new NPC, a new mini-biome, a new event, more furniture, more music, and much more.
Ancient Flier: Now moves faster, and shoots a special projectile in Expert Mode. To prevent the spam of Bone Harpies, a cap has been placed on his capacity to summon them.
Starplate Raider: Nerfed its star attacks, increased protection against piercing weapons
Infernon: Nerfed his projectile spam. In Expert Mode, the boss will transform into the Infernus Skull as a final form.
Dusking: Increased speed, power, and amount of attacks.
Ethereal Umbra: Greatly buffed its and the Ethereal Mirage's health.
Illuminant Master: Nerfed his teleportation range and his projectile spam.