Implementation of Roles in Six Sigma Methodology

There are many roles that that are used in the Six Sigma Methodology. While most of the roles below are used in many organizations Six Sigma implementation, it should be noted that they are not universal. The roles include:
Executive Leadership - Top level executives are responsible for vision and ultimately implementation of the Six Sigma Methodology. They also empower others to take initiative and ownership of the Six Sigma principles.
Champions - Champions are usually upper management that is responsible for the implementation of Six Sigma throughout their organization.
Master Black Belts - are usually hand picked by Champions to coach others within the organization on the Six Sigma methodologies. They allocate either all or most of their time to the Six Sigma methodologies. It should also be noted, that they usually have mentoring responsibilities to coach and train lower roles including Black Belts and Green Belts (see below)
Experts - while this role is not in every organization, it can play a huge role in major engineering or manufacturing sectors. They improve overall services, products, and processes for their end customers.