Riddles

[mneme]

[edits: credit added where it's due, and typos fixed]
I appear to be in a riddle mindset today, so you all get the "benefit." Two of these are very specific propper nouns, one is the more common sort of riddle:

I killed myself to make myself, and avenged myself shortly after.
He who wields me, built me, yet he is far younger than I.
I serve are those whom I was made to kill, and have done so since my birth.
What am I?
[answered by bigscary]

I drank from a king.
Yet kings have striven to drink from me?
What am I?
[first answered by bigscary]

Hermes's silver snake,
I speed but do not slither,
Burrow but do not dig.
What am I?
[incompletely, but correctly answered by nightface

Comments

[mneme]

As above; nightface's answer was close enough for #3 (also, water digs, and doesn't match the "hermes's silver snake" kenning, though a river might).

The grail one has a few features that point to it not being a sword:

Kings don't strive to drink -from- a sword, though they might strive to make their swords drink from others.
Many kings have been drunk from by swords, but the object of the riddle had only drunk from one king (which was one major clue not in the draft version of the riddle).