CHA is arguably the most important characteristic in the game (at least for ambitious characters) but is the easiest stat to improve in the game. For example:
Got a cool magical sword? +1 CHA.
Led a successful military expedition? +1 CHA.
So if you have at least a 16 CHA starting out, you are well on your way to becoming a Rune Lord. If your CHA is lower, don’t worry it can be trained as well. But if you decided to make CHA your “dump characteristic” then you have a long road ahead of you.
Very important – CHA is not Appearance, although they often overlap. There are plenty of people with a high CHA (magnetic personalities, presence, divine favor, etc.) who are not particularly good-looking. And there are plenty of people who might be considered good-looking who have a low CHA.
For comparison, most leadership in our world is bureaucratic rather than personal. Although I have certainly met a few 18+ CHA politicians and business leaders in my time.
If your goal is to become a Rune Lord, then you need a flashy magic object, lead a bunch of glorious activities that get the attention of people, and maybe train a point or two of CHA.