In Civilization VII, Dark Age Legacies are significant gameplay elements that offer players powerful bonuses at the cost of substantial penalties when transitioning between ages. Here's a detailed look at how they work:
What are Dark Age Legacies?
•Mechanics: Dark Age Legacies are triggered when a player fails to complete any milestones of a Legacy Path within an Age. When entering a new Age, players can choose from any Dark Age Legacy they've unlocked, providing a potent boost in one area but with a corresponding disadvantage. [Source: game8.co]
•Activation: Unlike Golden Age Legacies, which require full completion of a Legacy Path, Dark Age Legacies are automatically available if you fail to meet any milestones in a Legacy Path. [Source: civilization.2k.com, screenrant.com]
Examples of Dark Age Legacies:
Cultural Dark Age:
•Bonus: +1 Charges and Movement for Missionaries.
•Penalty: -3 Happiness in all settlements after founding a Religion and -6 Happiness in all settlements not following your Religion. [Source: newsweek.com]
Military Dark Age:
•Bonus: Lose all existing armies and settlements except for your Capital, but start with three full armies of cavalry and siege units.
•Penalty: This represents a drastic military reset but with the advantage of a significant starting force. [Source: newsweek.com]
Science Dark Age:
•Bonus: Gain a random technology boost every five turns.
•Penalty: -50% Science output, which could be strategic if you're not aiming for a science victory. [Source: newsweek.com]
Economic Dark Age:
•Bonus: +100% Production and Gold towards building or purchasing Rail Stations and Ports, +1 Resource Capacity in all settlements.
•Penalty: -25% Culture, potentially slowing down cultural victories or influence. [Source: newsweek.com]
Strategic Considerations: 
•Recovery and Pivoting: Dark Age Legacies can be used strategically to recover from a weak position or pivot your strategy. For example, choosing a military Dark Age Legacy after a setback might allow you to regroup and launch a new offensive.
•Risk vs. Reward: Players need to balance the immediate benefits against the long-term penalties. If your victory condition doesn't rely heavily on the aspect where you're taking a penalty, the trade-off can be quite advantageous.
•Player Strategy: Some players have discussed using Dark Ages intentionally to leverage the powerful bonuses for a specific strategy, especially if they can mitigate the penalties through other means or if the game's progression allows for a different approach to victory. [Source: forums.civfanatics.com, reddit.com]
Conclusion:
Dark Age Legacies in Civilization VII introduce a layer of strategic depth where players can turn a setback into an opportunity by carefully selecting which Dark Age Legacy to activate. They encourage players to adapt their gameplay, making decisions based on the current state of their civilization and the path to victory they are pursuing.
This system adds an interesting dynamic where players might not always strive for Golden Ages but might see strategic value in embracing a Dark Age for the right moment in the game.
