So believe me when I tell you that I was wrong, dead wrong. That kid from Vault 101 is the Last, Best Hope of Humanity.”— Three Dog
Reach level 20 while having Good Karma.
Reaching level 20 with Very Good karma also grants the achievement/trophy.
Behind the scenesEdit
In Fallout 2, according to President Richardson, a modified version of the Forced Evolutionary Virus is the last, best hope of humanity since it can cleanse the mutation. This karma title and achievement is probably a reference to this.