wrong, palpatine says it was been for a thousand year in episode 2, so i was forged about the time of darth plaugeis's death. that banch of the sith stared 1000 prior to plaugeis and it was around then. so it will fall about 2500 years
its impossible as far as im concerned because once an enemys dead they are never repalced. but in the first one on tatooine they do come back but there are only 4 and you don't get much XP