The former Blood Spear did not have this ability; it could only reject users of the same tier and kill them, but now the situation is slightly different.
It has this ability now!
As for the method to achieve this effect, it is certainly not the traditional rejection, but most likely a way to transform into a non-conventional life form, becoming an anomaly life form, thereby no longer existing as a weapon, so naturally others can't use it.
And this is the final desperate path for the Blood Spear. Without encountering the situation where the master is killed, it is unlikely to actively mutate into a special life form on its own, as its essence is that of a weapon, and losing the essence of a weapon is akin to death.
