What we already know
The corporation in charge of Westworld boasts a backstory more nebulous than the Man in Black's. Vague dialogue and the possibility of multiple time frames make it tough to determine which characters, aside from Dr. Robert Ford, have anything to do with Delos' origins. Here's a breakdown of everyone's ties to the corporation, based on the info we've received thus far:
Theresa Cullen: She's the Quality Assurance head at Westworld, and as such, she's one of our closest links to Delos. Her job entails monitoring the park's safety and standards, giving her power over the engineers and narrative artists. She also effectively acts as the board's messenger, liaising between people like Ford (the park's creative director) and Charlotte Hale (Delos' newly introduced executive director).
Logan and William: The black-haired bro is the scion of a wealthy clan whose family business is interested in buying out Westworld, which, he purports, is "hemorrhaging cash." It's unclear what Logan's family business is, and what his role in it might be, but we do know that William is Logan's EVP of upper middle management.
The Man in Black: He's a wealthy VIP who has been a park patron for years, and who, in Episode 4, threatens to kill a guest for bringing up his life away from Westworld. "Your foundation literally saved my sister's--" a young man begins to say, before the MiB cuts him off. What's this foundation, and does it have anything to do with Delos? As the seasoned visitor tells Dr. Ford at the end of Episode 5, he's not here for fun and games, or to make friends. He just wants to unlock the park's final level.
Dr. Robert Ford (Anthony Hopkins): He's creating chaos in the park with his elaborate new Wyatt narrative, and he views the Delos board members, whom he disdainfully calls "the moneymen," as obstacles. They want to secure his legacy, according to Theresa -- which sounds like a euphemism for delaying, or ending, his involvement with Westworld. But for Ford, Westworld isn't a business venture or a theme park; it's an entire world, one covered in his fingerprints.
The creative director also said in "The Stray" that, 30 years ago, things weren't as complicated. When Arnold was still around, there was much less corporate oversight. There weren't even guests -- just "pure creation." Regardless of whether you buy into the time-frame theories, Delos has overseen the park and its developments for at least the past several years, and the relationship between Ford and his corporate overlords can be, at best, described as antagonistic.