From the geological formation of the same name. When I learned that word as a mere child, I immediately thought it sounded cool. And I've used it as a nick pretty much since the internet.
Only problem is, it's usually taken on larger communities.
My friends back in high school used to call me Chrono, it comes from the Greek word Khronos which means time. The reason I was tagged with such a nickname was due to the fact that throughout my entire High school life, I was never late for a single class, not skipping nor wasting time with hanging about in the halls.
Kinda sad now that I think about it... but meh, It's a cool nickname.
An obvious gallicism of Achilles, I desired to create a character who perceives himself as infallible, whilst containing the odd flaw beyond those resident within most of his peers.
The Hellenistic tie also further implies that the character is a homosexual, as Achille is an even combination of flagrant truths and noxious stereotypes.
Actually, I just thought the name was endearing and built the character around that.
THE SYNDIC LEAGUES
(A co-operative of Rheinland's outlawed trade unions, determined to take the underworld for themselves.)
Wanted to pick up a name for a character long time ago and it popped out from my mind. Some years later I had to realise that this is a common name, not my mighty superpower unique virtual callsign...