To run a startup you need three personas represented by your founders:Hustlers, Hackers and Hookers.
The hustler is the founder who can breaks down doors, she unlocks segments, captures funding, she's makes sure the startup engine never stalls for lack of leads or funding.
The hacker is the founder who builds it. She is a McGyver and can build anything quickly. When there's a technical problem she can get it duct taped and bubbled gummed back up in giffy to keep the technical side of the business running.
The hooker, often called a designer, is the least known of the founder personas, but possibly the most valuable. His job is to love the customers. He listens to the customers emphatically and deeply understands what customers need, even when the customer can't describe it. This founder figures what should be built, how it should work. what it should look like, all within the constrains of the business model and technology.
Often startups don't have dedicated people for each of these roles, but the personas need to covered by the founders to achieve success.