Forbidden arts and dark Knowledge will teach your killers to strike the most vulnerable spots and deliver deathblows! Upgrading the Knowledge increases the damage caused by your killers.
| Level | Timber | Steel | Plates | Thoriars | Scrolls | Time | Requirements | Increased Slayer Offense | Influence | |
| 1 | 260 | 780 | 260 | 380 | 400 | 2w 4d 00h 00m 00s | 4 | 22M | ||
| 2 | 355 | 1.1K | 355 | 520 | 565 | 3w 2d 00h 00m 00s | 8 | 22M | ||
| 3 | 495 | 1.5K | 495 | 720 | 790 | 4w 3d 00h 00m 00s | 1st, | >2nd | 22.5M | | |
| 4 | 700 | 2.1K | 700 | 1.05K | 1 150 | 6w 1d 00h 00m 00s | 1st, | >6 | 22.5M | | |
| 5 | 1.05K | 3.1K | 1.05K | 1.5K | 1 600 | 8w 6d 00h 00m 00s | 2 | 22.5M | ||
| 6 | 1.55K | 4.55K | 1.55K | 2.25K | 2 300 | 13w 2d 00h 00m 00s | 2nd, | >9 | 23M | | |
| 7 | 2.35K | 6.95K | 2.35K | 3.4K | 3 300 | 20w 5d 12h 00m 00s | 4, | >4 | 23M | | |
| 8 | 3.6K | 11K | 3.6K | 5.25K | 4 750 | 33w 6d 12h 00m 00s | 6, | >5 | 23.5M | | |
| 9 | 5.75K | 17.5K | 5.75K | 8.35K | 6 850 | 57w 4d 12h 00m 00s> 1 Year(s) | 9, | >5 | 23.5M | | |
| 10 | 9.3K | 28K | 9.3K | 14K | 10 000 | 101w 6d 00h 00m 00s> 1 Year(s) | 14 | 24M | ||
| 25.41K | 76.58K | 25.41K | 37.42K | 31.71K | 252w 5d 12h 00m 00s> 4 Year(s) | 14 | 9 | 228.5M |
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