Usually, artifacts do not have a fully conscious spirit of their own, and the creators of artifacts purposely do not make fully conscious artifacts, as once an artifact becomes fully conscious, it can no longer be considered a 'tool.'
A 'tool' does not need to think for itself, or it would become less efficient when used by others to do their bidding without the permission of the 'tool.'
A 'tool' just needs to be useful when it is needed.
Raika, the Sword of Cosmic Order, is one of the greatest examples of a 'tool' gone completely wrong.
She gained a full consciousness of her existence and thus became unusable for most everyone.
Even King Allen could only use her strength as a friend and couldn't even force her to exert even the slightest bit of her power unless she wanted to do it herself.
Eventually, she even left him after some disagreement, proving that an artifact with a fully developed self-consciousness can be a big problem.
