en_tn_condensed/rev/06/11.md

until the full number ... were to be killed

This implies that God had decided that a certain number of people should be killed by their enemies.

their fellow servants and their brothers and sisters

This is one group of people described in two ways: as servants and as brothers and sisters. Alternate translation: "their brothers and sisters who serve God with them" or "their fellow believers who serve God with them"

brothers and sisters

Christians are often spoken of as being one another's brothers and sisters. Alternate translation: "fellow Christians" or "fellow believers" (See: rc://en/ta/man/translate/figs-metaphor)