I will look at character representations first. Now we will look at characters. Many standards exist for representing characters on computer systems. You could invent your own until computers started being networked. They also fail to cover extensions.
Character sets are remarkably arbitrary.
As long as everyone agrees, it works great. England has problems. There are other character sets to solve some of the problems. But, as yet, no character set solves all of the problems. The total number of possibilities will be determined by the number of bits used to store the number.