The Overseer, the being able to match Tyrant

Ah the overseer. The Tyrant's third competition other than the hero and the collector

The Overseer is able to match the Tyrants strength with is speed and agility.

The Tyrant can let the Exo-Inker's mechs deal with the overseer

He's too fast, he'll easily escape and find the Tyrant.

Then the hero who vanquished the Calamity can take the overseer down, unless the overseer is a good guy

Overseer is more of an Antihero

Here's a secret about The Overseer
(He's not Eggyhead, but he is an egg)

Of course he's an egg

What? Ya don't like it?

I just think the egg thing is... repetitive

Yes. Read my username.

I know

What is the gem in his chest

An incredibly powerful compressed version of the master emerald (from Sonic)