Sander Kaasjager, who also goes by the pseudonym Vo0, is a former Dutch professional player of the first person shooter game Painkiller, born in Naarden. He was formerly signed on to play for the electronic sports team Fnatic. When the Cyberathlete Professional League, World Series of Video Games, and other tournaments dropped Painkiller in favor of Quake 4, Kaasjager retired from professional gaming on June 21, 2006 to pursue his studies for the upcoming college semester.
Originally starting with Quake II, Kaasjager later rose to widespread popularity with the release of a self-made montage of highlight footage (or "frag video") from the game Challenge ProMode Arena. Which showcases Kaasjager's unique aggressive style of playing.
He made a comeback to competitive gaming on April 30, 2007, participating in the World of Warcraft competition of the World Series of Video Games representing Fnatic once again.
Kaasjager has won more professional Painkiller tournaments than any other player. He has competed in multiple professional gaming tournaments around the world. Kaasjager won two world championship titles, one with the CPL, and one with the ESWC, both in 2004.
In 2005, Kaasjager competed in the 2005 CPL World Tour, in which he won at five out of nine stops and earned $223,000. Kaasjager was named the Most Valuable Player of the tour. Overall, Kaasjager won over $250,000 in prize money at professional Painkiller tournaments, more than any other player.
After retiring, he has been known to play Quake 3 CPMA, Warsow, QuakeWorld and Quake Live.