How to Defeat A Servant
When a Heroic Spirit emerges into this world, he first acquires a Spiritual Core. The Heroic Spirit then materialises as the body envelopes this Spiritual Core. In order to defeat a Heroic Spirit, one must inflict damage to the Spiritual Core. The Spiritual Core gradually diminishes as a result of massive magical energy expenditure or sustaining bodily damage. Under these adverse conditions, the Heroic Spirit’s expenditure of magical energy will escalate, and should damaged be inflicted through powerful magical energy, curse, or Noble Phantasm, the Spiritual Core will be destroyed, and the Heroic Spirit will no long be able to remain materialised. The heart and head are connected directly to the Spiritual Core, thus they are the weaknesses of Heroic Spirits. Sustaining damage at these locations will significantly weaken the Spiritual Core.
Battle of Servants
The battle between Servants can be called a process of gradually shaving off the magical energy that forms the their bodies. Attacks that consume a great amount of magical energy will inflict a massive amount of damage on the opponent, but it will also weaken yourself in the process. In order to inflict a great amount of damage with minimum expenditure of magical energy, it is necessary to collect intelligence regarding the enemy and assault his weakness.