I disagree with Adam below.

DevOps started out as a term for the inclusion of server people in the app development, but that has mutated quite a lot. In fact, nowadays developers have to care less about servers than ever before. It's the era of Platform-as-a-Service, container orchestration and continuous, unattended deployments.

Today DevOps is all about automation. DevOps people are there for one task: Automate the deployment pipeline! They are supposed to create, streamline and maintain the workflow from development, through QA and out the door to Production.

When you hire DevOps people, you do it because you have a lot of development going on, a lot of constant change, and you worry about not shipping often enough and/or your code quality not being up to par. The DevOps guy (or gal) should be able to introduce a CI and/or CD tool that integrates with your code repositories, automatically runs all unit and ideally integration tests, and if all green, deploys each commit straight to the target environment (be it Prod, UAT or whatever).

What does a DevOps dude do in an early stage startup? Enable fast and streamlined continuous integration and deployment.

I'd like to add something more: make sure the person is able to speak to both teams (i.e has knowledge in both OPS and DEV). Devops is not only about automation/tools, it is also about communication between the teams.