Speaking with the paper, he says the name of the second character is Walter and spoke about what he’s been allowed to say by the studio:
“I am allowed to say I am playing two robots – Walter and David. I think what’s great about it is that Ridley has gone back to the original DNA of Alien, the horror element of that. But is also has the scope and the scale of Prometheus. Ridley has cut it already. He is a machine. He is an incredible human being and he was in such good form. He is such an imaginative and mischievous figure.”
AVP Galaxy offered a few more details about the character, saying Walter is a more advanced version of David and is distrustful of David 8 because the older model has gone a decade without any form of maintenance or upgrades. “Alien: Covenant” is set for release on August 3rd.