The Sword Of Plot Advancement is the offensive or defensive item that the central plot of the game revolves around, and whose collection by the player signifies that they are now capable of advancing to the end of the game. It thus marks the end of the Second Act. Alternatively, it may be gained at the beginning of the Second Act, if it is important to game mechanics, and marks the beginning of the adventure proper. Most of the time, since said sword acts as an Amplifier Artifact, it is the only Achilles Heel of the immortal or Nigh Invulnerable Big Bad. Examples of the first type: