Why do I need Stronghold Tier 10 before the Reign ends?

The "Heirs of the Dragon" campaign (11 chapters plus an epilogue, ~40 days) requires Stronghold Tier 10 before the Reign ends to claim the campaign rewards.

If you finish the Reign at Tier 9, you lose those rewards — and since everything resets, you start from scratch the following season.

Concretely:

• Plan your tier climb from the start of the Reign, don't linger at Tier 7-8.
• Keep an eye on the campaign's day counter.
• Prioritize wood + stone (construction resources) and the third builder to move faster.

Tier 10 is your non-negotiable seasonal deadline if you want the campaign loot.