Things to go along with The Ancient: (The boss I created)

The Ancient can be spawned with in an Ancient Shrine (new structure) These are incredibly rare structures within soul sand valleys. They look like large boulders embedded in the valley made out of  soul rock, which can only be broken and collected with netherite pickaxes Inside is a fossil. Inside is single blue block. When it’ broken, the Ancient Shrine is destroyed, sending soul rock flying everywhere. The player is knocked back a good distance. The soul rock is sent flying back together to form The Ancient.

When The Ancient is finally killed, it explodes, leaving behind a fossil, loads of soul rock, and it drops one Soul Essence. Soul essence can be crafted together with any Netherite item, giving that item a blue glow, and, for netherite armor, increases the armor toughness by 1, and adds temporary fire resistance (like the turtle helmet but for fire resistance) combined armor with Soul Essence increases the duration of fire resistance, full armor gives permanent fire resistance. For tools, it adds even more durability, for the axe, it adds even more knock back, and for the sword, it adds more damage and Soul Fire Aspect, lighting the victim on fire, but the fire does more damage (and the fire is blue)