King Midas. not self-control. wished for everything he touched to turn to gold.
the self-control one? got me.
If you go to Wikipedia you'll find a whole page of information - it's a lot to read through but I think you'll find exactly what you're looking for.
*how self-control benefited a character*
I think them being able to control what they did allowed them to keep going without any boundaries or someone to sit there and say "you're forbidden to do this".
*how not having self-control contributed to their downfall*
This is when one person is pretty much ruling everything and nobody else's opinion matters, not even the smallest bit. So if that head person makes the wrong decision, everyone goes down hill because they aren't self-controlled and cant make their own decisions.