For those who don't understand how drac can be in this game if it is a SotN sequel, you should remember that only five years passed between RoB and SotN, with drac in both. The fact is that drac can be revived by his minions if there is a human sacrifice. The 100 rule is only relevant in regards to him resurrecting "naturally".
In other words, if drac's minions don't resurrect him within 100 years, he will resurrect on his own. However, as far as I know, if he is resurrected by his minions, he will lack his full power at first. So, based on this, he is stronger when he resurrects "naturally".