his repertoire includes virtually all the great german bass roles , such as mozart 's figaro , leporello , and don giovanni , pogner in wagner 's die meistersinger , king heinrich in lohengrin , gurnemanz in parsifal , fasolt , hunding and wotan in the ring des nibelungen , oreste in strauss 's elektra as well as ramfis in aida , filippo ii in don carlo , méphistophélès in faust , escamillo in carmen , gremin in eugene oneguine and the title role of boris godunov .