Well, this was one of the only constructions I ever fashioned specifically to house a spiritual essence, so it is somewhat singular. I donated my own blood to that end. Later aradia-bots, I am told, had more of my blood, so I likely built them slowly, over time to avoid excessive blood loss when creating the legion.

Generally, I try to keep to the willing, but given the nature of the hemospectrum I'll confess that 'willingness' can be subject to perspective with the lowest castes.