Erik Wolpaw, best known as one of the more prominent writers at Half-Life and Steam house Valve Software, is leaving the company, according to a tip received by Gamasutra that matches up with a Facebook post from Wolpaw and a Twitter post from fellow Valve expat Marc Laidlaw.

It’s a notable departure for Valve. Wolpaw, who joined Valve in 2004, has credits including Half-Life 2: Episode One, Episode Two, Portal, both Left 4 Dead games and other highly-notable titles.

Wolpaw’s resignation comes a little over a year after Laidlaw, also an influential Valve writer, revealed that he’d left the company. Laidlaw’s credits include many of the same games on Wolpaw’s resume.

There’s no word yet on exactly what Wolpaw is up to next, though he’s credited as a writer on the upcoming Double Fine game, Psychonauts 2.

For an in-depth interview on Wolpaw and Laidlaw's work at Valve, check out this joint interview from 2009.