Your architects have suggested adding a system of secret tunnels, traps, and ambush points to the Town walls. They say this will help you and your allies defeat more enemies. Upgrading this Knowledge increases the offense of your troops when defending Towns.
| Level | Gold | Soul Shard | Time | Requirements | Troop Offense When Defending Towns | Influence | Hero’s Experience |
| 1 | 125K | 24.5K | 48w 4d 00h 00m 00s | Troop Offense When Attacking Towns II 1, Oracle 36 | 1% | 15K | 37.5K |
| 2 | 190K | 36.5K | 72w 1d 00h 00m 00s> 1 Year(s) | Troop Offense When Attacking Towns II 2, Oracle 36 | 4% | 33K | 47.5K |
| 3 | 255K | 54K | 15w 2d 00h 00m 00s | Troop Offense When Attacking Towns II 3, Oracle 37 | 8% | 74.5K | 60K |
| 4 | 320K | 80.5K | 158w 6d 00h 00m 00s> 3 Year(s) | Troop Offense When Attacking Towns II 4, Oracle 37 | 13% | 170K | 76K |
| 5 | 385K | 120K | 235w 6d 00h 00m 00s> 4 Year(s) | Troop Offense When Attacking Towns II 5, Oracle 38 | 18% | 380K | 95.5K |
| 6 | 450K | 180K | 350w 2d 00h 00m 00s> 6 Year(s) | Troop Offense When Attacking Towns II 6, Oracle 38 | 25% | 860K | 120K |
| 7 | 525K | 265K | 520w 1d 00h 00m 00s> 9 Year(s) | Troop Offense When Attacking Towns II 7, Oracle 39 | 34% | 1.95M | 150K |
| 8 | 635K | 390K | 772w 3d 00h 00m 00s> 14 Year(s) | Troop Offense When Attacking Towns II 8, Oracle 39 | 45% | 4.4M | 190K |
| 9 | 840K | 580K | 163w 6d 00h 00m 00s> 3 Year(s) | Troop Offense When Attacking Towns II 9, Oracle 40 | 58% | 9.9M | 230K |
| 10 | 1.3M | 860K | 1 703w 2d 00h 00m 00s> 32 Year(s) | Troop Offense When Attacking Towns II 10, Oracle 40 | 75% | 22.5M | 285K |
| 5.03M | 2.59M | 4 040w 5d 00h 00m 00s> 77 Year(s) | 75% | 40.28M | 1.29M |
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