Dossier
Ernesto never shows up on screen. He's a voice, heard through a phone during the tense opening minutes at Raymond's stash house, while Jason and Lucia are inside collecting product for Boobie Ike.
The call doesn't go the way it's supposed to. Whatever gets said, it lands badly enough to register on everyone in the room. Not long after, the police hit the building.
What exactly Ernesto is to the operation, and what the call actually meant, isn't spelled out on screen. There's a version where he's a supplier getting nervous. There's a version where he's the reason the police knew where to look. The footage doesn't pick one, and this entry won't guess on his behalf.