Last time we left our beloved Harold he had gone back to his roots. That is to say he was literally rooted in place by his companion Bob. Depending on your choice Harold is either alive and still rooted in place (you monster), or he is dead (you bastard). However it is still unacceptable to think this staple of the fallout universe will not return. That is why I speculate that Harold is in fact dead, however much as trees spread their seeds, so have Harold, and while we will not meet Harold again we will in fact meet his off spring, who have sprouted out of the ground in the wake of his demise.