Meso'ed said: In a way, it's because of Kiritsugu that the Grail becomes tainted. If Kiri didn't shoot Kayneth, he wouldn't of commanded Lancer to kill himself.
The grail had been tainted since the 3rd War due to the Einzberns summoning Avenger. When he was killed, his spirit went back into the Grail and corrupted it. So Lancer has nothing to do with the corruption of the Grail.
are you trying to be my enemy?He is Lancer's Master....Then why did you cover that man.... youI thought I'd die from that...No matter what happens... I am your ally..No way...I guess it's because you lookedlike you would lose it for real.