Tough steel and time-proven tactics make your army invincible! Upgrading this Knowledge allows you to increase your troops' defensive efficiency during defense.
| Level | Scrolls | Precious Dust | Gold | Time | Requirements | Troop Defense Increase During Defense | Influence | |
| 1 | 250 | 10 | 41.5K | 1w 12h 00m 00s | 1 | 13M | ||
| 2 | 330 | 15 | 53K | 1w 3d 12h 00m 00s | Army defense in Onslaught 2 | 2nd, | >5 | 13M | |
| 3 | 435 | 15 | 71.5K | 2w 1d 12h 00m 00s | Army defense in Onslaught 3 | 5 | 13.5M | |
| 4 | 585 | 25 | 97.5K | 3w 2d 00h 00m 00s | Army defense in Onslaught 4 | 8, | >5 | 13.5M | |
| 5 | 810 | 35 | 145K | 5w 2d 00h 00m 00s | Army defense in Onslaught 5 | 14 | 13.5M | |
| 6 | 1 150 | 50 | 230K | 8w 6d 12h 00m 00s | Army defense in Onslaught 6 | 20 | 13.5M | |
| 7 | 1 650 | 80 | 380K | 15w 5d 12h 00m 00s | Army defense in Onslaught 7 | 30 | 14M | |
| 8 | 2 450 | 140 | 665K | 29w 3d 00h 00m 00s | Army defense in Onslaught 8 | 40 | 14M | |
| 9 | 3 600 | 255 | 1.25M | 57w 4d 12h 00m 00s> 1 Year(s) | Army defense in Onslaught 9 | 50 | 14M | |
| 10 | 5 500 | 490 | 2.4M | 118w 5d 12h 00m 00s> 2 Year(s) | Army defense in Onslaught 10 | 60 | 14.5M | |
| 16.76K | 1.12K | 5.33M | 243w 6d 12h 00m 00s> 4 Year(s) | 60 | 5 | 136.5M |
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