Looking for a word meaning a person who thinks he's the one to do everything

Since English isn't my first language I think this is the best place to ask this question. I had no luck while looking for an answer on Google.

I'm looking for a word describing a person that thinks they’re the one and only person doing everything (e.g. in a business) while it is not necessary the case.

It could also be a word with a meaning similar to a person claiming all the success of a business but none of the failures.

Solution 1:

"prima donna" would fit your first description pretty well.

If you just want to focus on "a person who thinks he is the one to everything," you could try "control freak" or "micromanager."