This study illustrates how the power relation between the trustee and principals are experienced and maintained in proportion to the missions design. The main focus lies on understanding of how trustee perceives and applies the mission`s cornerstones and how power can be expressed in the relationship between trustees and principals. Nine semi-structured interviews were conducted with trustees whose principals were mentally disabled. The interviews were then analyzed with the support of Foucault's concept of discipline, knowledge, control, surveillance and reward/punishment and Tilly's theory of persistent inequality We have obtained an understanding of the complexity of the assignment regarding the mission`s cornerstones who goes into every other, and all respondents agreed that the cornerstones should be considered as a whole. We concluded that the trustee on the basis of the mission's design possesses a power that is necessary and important to have regarding the relation to his principal and its social network. Half of the trustees were well aware of the power they possess; however, all agreed that power is a negatively charged word that not necessarily needs to be operated in the guardianship. We could, based on empirical data, see that the power is used in various ways, both directly and indirectly against their principals and its social networks.