We propose a human-will-based approach to constructing a coexistence system in which a robot is assumed to assist the will power of a subject while reflecting his intention and desire. We discuss the model of human's will associated by the work - psychological mind reading, and identify the advantages of the system in which the robot guides the the subject manipulating along the path intended by him. Then, we describe two major techniques with experimental results: 1) estimation of the human-intended path pattern from the previously assigned one by proposing a modified algorithm of hidden Markov model; and 2) merging of the human's force feeling pattern into the desired one by proposing a field impedance equalizer which allows both the human to express his desirable field-dependent force/speed feeling and the robot to display the impedance along the previously estimated path. Finally, we conclude the study with some comments on future works.