Terran Envoy

But when an envoy from Earth (the player character) has been elected by the UN and enters the alien ship - it turns out we are actually being abducted: the Ubbermenscha demands that we identify the very bad guy among the other Council members called the Usurper in order for humanity to be admitted to the council. The player has to travel and investigate eight star systems with several planets orbiting around each star, finding different aliens and talking to them, mining different types of crystal that have to be exchanged for the valuable information - and discovering the true nature of each Council member - their friends and enemies, their preference in crystals, as well as their level of honesty, friendliness and loyalty to the Ubbermenscha - before identifying the Usurper and destroying his planet as instructed.