In Loop Hero the Oblivion card is a single-use activation card that is acquired at the beginning of the game. It is a unique and powerful card which can be placed on any tile on the map, and it allows you to destroy it along with any creatures that inhabit it by casting the Lich's Oblivion spell. If the tile you used the Oblivion card is on the Road the tile will return to being a Wasteland. If your character is standing on the targeted tile when the Oblivion card is placed they will be unaffected.
Oblivion cards should be used wisely and ideally stockpiled and saved for the boss battles where they will help you considerably. An Obliion card can destroy the Lich's Palace tiles, reducing the Lich's health and damage by 5% each making the battle easier. The Oblivian card can be used to destroy Bandit Camps and Goblin Camps. If it is a Bandit Camp that the Oblivion card destroyed the Bandits that it spawned are also destroyed. Oblivion cards can also be used to destroy Groves and Villages, causing nearby Blood Groves to become Hungry Groves and Wheat Fields to become Overgrown Fields.
Another use of Oblivion cards is to gain more resources by using them on a Rock or Mountain so you make up a Mountain Peak and the surrounding tiles go back to what they were before becoming part of the Peak. Then place another Rock or Mountain to replace the destroyed tile to form the Mountain Peak again and gain the resources from creating it a second time. You can also use the Oblivion card to roll back the boss tracker slightly by deleting a tile, it will however still summon the boss if it is the final card played.
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