A person who actually cares about the pain you solve, for this reason pushes for your product, and is or has access to decision-makers.
See The most important buying roles
A Champion is the person who looks for your product in the market, pushes within their organization selling the product on your behalf, and becomes your supporter and evangelist when the product has been purchased and their pain has been solved.
You should try to attract Champions through your demand generation activities.
Once you connect with one, you should stay well connected throughout the whole purchase process and sell to them until they are convinced.
Champions may introduce you to other roles, if required. If you are selling up-market, they will become the keystone of your multi-threaded strategy as you connect with other people.
In some cases they may not connect you with a Decision Maker, but rather sell to the Decision Maker on your behalf. In this case, you should provide them with all required resources.
