Real numbers and imaginary numbers are collectively called complex numbers, which are the largest number fields in general mathematics.

But numbers are defined by people. There are more people in the world who are useless to numbers, so there are numbers.

Hamilton once defined quaternions in history. This group of quaternions constitutes the first division ring in history.

So as long as there is no problem with the defined number and there is no contradiction with the known axiomatic system, it is ok.