Now through November 20, everyone aged 18 or older in the US who donates blood at any blood donation center in the US can earn free content for Diablo IV. Blizzard also announced a special sweepstakes where players can win a PC with real human blood in it.

People need to log their blood donation on the Blood Harvest website to be eligible for the free content. Blizzard is aiming to reach a collective 666 quarts of blood donated. But even if the campaign falls short, players will earn a reward at 33% and 66% of the goal, with the final reward going out if the campaign reaches the full 666-quart target.

666 quarts of blood works out to 1,332 donations, Blizzard said. If the full amount is reached, everyone Diablo IV player--whether they donated blood or not--will be entered into a sweepstakes to win a custom-made PC featuring real human blood as part of its liquid cooling system. Here's what that looks like: