Mercs as agents on overseer

Hi,

i just started with overseer, and have 2 unloked agents and at level 3, i read somewhere that you can use mercs if you unlock them to hire anywhere, i unlocked 2 mercs, the 10 year tank one and the healer from gorowyn,
but i dont know how to get them to show as agents on the overseer screen,

am i missing something like a quest or something.

thanks in advance

They are not agents, but boosts. Just like the familiars.

Mercenaries don't become agents. You use them elsewhere in the Overseer panel. The wiki has more info on the Overseer Feature.