A lot has changed since Satya Nadella took over at Microsoft a little more than a year ago.

Windows no longer rules the roost. The energy has shifted away from big expensive software to "cloud" services. It's investing in cutting-edge products like HoloLens. Morale is better than it's been in years, according to long-time employees.

But Nadella can't do it alone. Who's helping him out?

We talked to some people close to the company to find out who the most important execs are under Nadella right now. Here's what we heard.