And I Must Scream:- If you refuse to take part in the Grail War when you happen to be taken to the church for the first time, Illya proceeds to brutalize Shirou and torture him devoid of killing him. The first ending achievable benefits in Berserker leaving Shirou a disembodied head, which Illya will maintain alive and torture for as long as she pleases. It's the sword Caliburn, which Shirou assignments in order to defeat Berserker.