A True Hero is pretty easy even if it sounds hard. Just be online while the Nemesis is close to be defeated. than wait a while, start the mission against the nemesis and give up,a-fter that the remaining RP will be updated. If it is still too much it again. Sooner or later it will show 0 RP, yes it stops at 0 but you can still fight it. (dont go to main menu or loose connection) when it reached 0