Source: Chronicles of Bilrach Part 14

Year 1573 of the 4th Age:

Forty years have passed since my last entry and finally, this area is completely self-sustaining. A working chain of production has been created amongst my slaves. The digging should be far more efficient and, more importantly, I have a solid rearguard if any choose to come after me. As if anyone would try to follow in my footsteps now! On the subject of slaves, I've had great success in my breeding program. I've taken the strength of the giants, the skin of the goblin and the size and basic intelligence of a human, and created a barely adequate but much-improved slave. Conditioning has sped up progress also. I've even bred them to believe pain is good for them! They'll literally work until they drop dead where they are!

Zamorak be praised!