Wrong Right From The Start.

Since there were nobles in the village taking part of the supply of the energy water it falls on the lamp bearers to protect the villages.

No one else other than the lamp bearers will protect them. After all, the lamp bearers made the rule, so they have to enforce it.

If they don't offer protection to the villagers, then the villagers will be killed or bullied. The villagers can also willing give up a certain portion of their supply to others for protection. But if they do this, many of them will die because of the reduction in the energy water.

To prevent all of these deaths, Captain Sheckel has taken it as her responsibility to protect all the villages under her jurisdiction.

This is a job that the lamp bearers do without any benefit because they don't take from the spirit spring of the villages at all. So they protect the surrounding villages free of charge.