What are characteristics of an oligarch?

The ones that hold the power are a small portion of the populace

The ruling class is typically the Wealthy (think Saudi Prince), Powerful (think Franco or Charvez), Ruthlessness (Think Hitler or Stalin), or Religious or Politically powerful (think of Anjem Choudary (emom) or Saddam Hussein)

Usually controlled by a few powerful families that raise their children to 'inherit' the power.

Most of the European Monarchies in the world started this way

In Oligarchies the people have little or no rights or power

Note:

The Word Oligarchy is Greek for 'few' and 'rule', and means just that few people rule.