Added in 3.0.0:
Patchnotes from 3.0.0
[Feature] Resource hideouts
In Game Description:
Basic: A portion of the crystal stocks will be stored here safe from plundering. The Den does not expand the overall storage capacity.
Detail: The capacity of the Crystal Den shows how much crystal is protected from plundering. The better the Den is upgraded, the more resources can be protected from attackers. Espionage probes are able to detect the upgrade level of a Den as well as the amount of hidden resources. The storage capacity is not expanded as a result of the Den.
Requirements:
Crystal Storage (Level 2)
Is Required for:
N/A
| Level | Metal Cost | Crystal Cost | Storage Capacity | Increment in Storage Capacity |
| 1 | 2645 | 1322 | 1610 | 1610 |
| 2 | 6083 | 3041 | 2804 | 1194 |
| 3 | 13992 | 6996 | 3878 | 1074 |
| 4 | 32181 | ? | 4882 | 1004 |
| 5 | 74017 | ? | 5836 | 954 |
| 6 | 170241 | ? | 6752 | 916 |
| 7 | 391554 | ? | 7639 | 887 |
| 8 | 900576 | ? | 8500 | 861 |
| 9 | 2071325 | ? | 9340 | 840 |
| 10 | 4764048 | ? | 10161 | 821 |
| 11 | 10957312 | ? | 10966 | 805 |
| 12 | 25201818 | ? | 11757 | 791 |
| 13 | 57964181 | ? | 12534 | 777 |
| 14 | 133317617 | ? | 13300 | 766 |
| 15 | 306630520 | ? | 14055 | 755 |
(You need to spend more than 500M metal and 250M crystal to hide only 14k metal. Isn't that stupid; who would want to build such a facility?)