Bloodpolis was a dangerous spell in more ways than one.
It's a devastating spell utilized only by vampires. Upon being cast, it conjures a dense cloud of crimson blood.
This dark and ominous technique involves the vampire channeling their own essence and life force, transforming it into a swirling, ethereal mist.
Other vampires could easily traverse in this crimson mist and fight with utmost proficiency since it's a spell cast by their own kind.
And fighting in a cloud of blood is their domain for obvious reasons.
When unleashed, the cloud envelops the immediate area, obscuring vision, and disorienting opponents.
The blood within the cloud is imbued with vampiric powers, making it highly corrosive and capable of weakening or even incapacitating those who come into contact with it.
That's why, no spell could ever be cast inside the Bloodpolis at its full potential since it would immediately be corroded.