Steward

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A steward is a headmate responsible for maintaining the system's health (both mental and physical) and its responsibilities (such as childcare, schoolwork, chores, and hygiene), oftentimes in the absence of other headmates.

In essence, stewards keep the lights on. This is a general umbrella term including any headmates that are called to the front for specific important work.

History
Steward was originally coined as a synonym to "taskdoer", but has since adapted to a more distinct term.