Another question is: would the most immediate or the most distant ancestor possible count as the best option for Voldemort? If the most distant, then he'll probably be wanting Salazar Slytherin's bones. If their location is known.
A hominid fossil might have no living descendants at all.
I think a fossilized hominid might have worse than average chance of having no living descendants too: To be fossilized they have to undergo a fossilization event, which is probably correlated with disaster: and given that ancient human did not stray far from their genetic siblings (and progeny) this probably indicates a high chance of that disaster affecting their progeny. I certainly wouldn't rely on it.
Nevertheless, given my cultural heuristic for what counts as most important, it would probably be father (in terms of how much various cultures put a value on either the father or the mother), or most recognized powerful ancestor (Salazar Slytherin in this case).
- This thread has run its course. You will find newer threads in the discussion section.
Another discussion thread - the fourth - has reached the (arbitrary?) 500 comments threshold, so it's time for a new thread for Eliezer Yudkowsky's widely-praised Harry Potter fanfic.
Most of the paratext and fan-made resources are listed on Mr. LessWrong's author page. There is also AdeleneDawner's collection of most of the previously-published Author's Notes.
Older threads: one, two, three, four. By tag.
Newer threads are in the Discussion section, starting from Part 6.
Spoiler policy as suggested by Unnamed and approved by Eliezer, me, and at least three other upmodders:
It would also be quite sensible and welcome to continue the practice of declaring at the top of your post which chapters you are about to discuss, especially for newly-published ones, so that people who haven't yet seen them can stop reading in time.