Tough steel and time-proven tactics make your army invincible! Upgrading this Knowledge allows you to increase your troops' defensive efficiency during defense.
| Level | Ale | Timber | Steel | Plates | Thoriars | Scrolls | Time | Requirements | Troop Defense Increase During Defense | Influence | |
| 1 | 600 | 600 | 600 | 600 | 400 | 400 | 2w 1d 00h 00m 00s | 4 | 22M | ||
| 2 | 820 | 820 | 820 | 820 | 545 | 565 | 2w 5d 12h 00m 00s | 8 | 22M | ||
| 3 | 1.15K | 1.15K | 1.15K | 1.15K | 760 | 790 | 3w 4d 12h 00m 00s | 1st, | >2nd | 22.5M | | |
| 4 | 1.65K | 1.65K | 1.65K | 1.65K | 1.1K | 1 150 | 5w 12h 00m 00s | 1st, | >8 | 22.5M | | |
| 5 | 2.35K | 2.35K | 2.35K | 2.35K | 1.6K | 1 600 | 7w 2d 12h 00m 00s | 2nd, | >4 | 22.5M | | |
| 6 | 3.5K | 3.5K | 3.5K | 3.5K | 2.35K | 2 300 | 11w 12h 00m 00s | 3rd, | >3rd | 23M | | |
| 7 | 5.35K | 5.35K | 5.35K | 5.35K | 3.55K | 3 300 | 17w 2d 12h 00m 00s | 4, | >8 | 23M | | |
| 8 | 8.3K | 8.3K | 8.3K | 8.3K | 5.55K | 4 750 | 28w 2d 00h 00m 00s | 6, | >9 | 23.5M | | |
| 9 | 13.5K | 13.5K | 13.5K | 13.5K | 8.8K | 6 850 | 48w 00h 00m 00s | 9, | >9 | 23.5M | | |
| 10 | 21.5K | 21.5K | 21.5K | 21.5K | 14.5K | 10 000 | 84w 6d 00h 00m 00s> 1 Year(s) | 14 | 24M | ||
| 58.72K | 58.72K | 58.72K | 58.72K | 39.16K | 31.71K | 210w 4d 00h 00m 00s> 4 Year(s) | 14 | 9 | 228.5M |
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