Xingyue: I Will Start a Holy Grail War

By some kind of chance, Shiraishi Xiu, who traveled to the Xingyue world, gained Alaya's favor and became the selected special [Guardian], and subsequently received three opportunities to reasonably interfere with the world. In order to fulfill his duty as a guardian, and also to reach the legendary crown and control the source, Shiraishi repaired human nature and personally created the Holy Grail War in Fuyuki City. He formed the same front with "heroic spirits" from different worldviews and officially embarked on a journey to end the evil in this world. (Note: The heroic spirits summoned by the protagonist belong to different anime worldviews.) The three interference rules are as follows: 1. Expand the existing spiritual veins in Fuyuki City and expand the scale of the existing Holy Grail War to twice its original size. 2. As a guardian, Shiraishi Xiu has obtained the identity of a local hidden magician and has excellent magic qualifications. 3. Obtain the magic inheritance [Causal Interference] exclusive to the Holy Grail War. According to its principle, the protagonist can obtain Noble Phantasms or inherent skills related to heroic spirits through overdraft of cause and effect. (Note: When the enemy heroic spirit exits the field, the protagonist can use this to activate reverse inheritance magic, thereby obtaining attribute enhancements that directly affect himself) (The plan of this book is to use Xingyue as the main world. At the same time, according to the setting, after the protagonist completes the summoning of non-native heroic spirits, he needs to repay the cause and effect, so it will have a comprehensive attribute)