I need a word for a boss/ leader who demands the best and also does the best themself.

**Examples:**

1. He asks the team to work late until 1am and he does it himself too.
2. He demands that every member of the team meets a ridiculous sales target and he meets it himself and surpasses all.
3. He asks his employees to come to work even if they're ill and it turns out he himself comes to work even though he's severely ill.

The word could be an adjective or a noun.