If the daughter of a night hag avoids her mother long enough can she delay becoming one too?

Question

The daughters of other hags all seem to fully turn into them automatically once 13, except with night hags according to lore. With them it’s said that there must be 13 rituals done on their daughters or the transformation doesn’t occur.

So for campaign purposes I have to ask: does this mean that it’s possible for a daughter of a night hag to be encountered who is older than 13 and thus far been able to evade their mother and being converted? Can it be delayed with them from the usual mandatory age?

And as an aside, if it is possible and such one is encountered, would they be a regular human e.g. stats wise or would there be differences? And would spells used by a party that could detect and reveal a hag also detect them?

Answer 1

The 5e Ecology of Night Hags does not include ritual transformation

From the 5e Monster Manual:

Monstrous Motherhood.

Hags propagate by snatching and devouring human infants. After stealing a baby from its cradle or its mother's womb, the hag consumes the poor child. A week later, the hag gives birth to a daughter who looks human until her thirteenth birthday, whereupon the child transforms into the spitting image of her hag mother.

Hags sometimes raise the daughters they spawn, creating covens. A hag might also return the child to its grieving parents, only to watch from the shadows as the child grows up to become a horror.

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The Ecology of Night Hags in previous editions included ritual.

For example, an article expounding on it in Dragon Magazine 324

Night hags reproduce in a manner exceedingly foul to mortal minds...

At the end of this period, the night hag gives birth to a dark-haired female child otherwise indistinguishable from others of her mate's species. Having no concept of maternal instincts, night hags always foster their children...

At any time between the child's first birthday and puberty, a night hag might return to perform a series of despoiling rites that cluminates in the child's transformation into a normal night hag.

The process begins with an initial visition...

After this initial ritual, the night hag must return three times, each visit thirteen days after the last. On these visits, the night hag must suckle the child and feed it the flesh of a living larva, a process that takes an hour.

Here's the take on your question specifically:

If any of these feedings are interrupted, or if the night hag can't access the child by the end of the proper day, the child cannot be transformed into a night hag.

A similar yet abbreviated description of the reproductive cycle is in the 3.5 MM.

Answer 2

An interrupted ritual of a night hag will cause the hag to leave the child. the child will be prone to sorcerous magic or might be approached later by it's mother to form a warlock pact. in very rare cases, if the hag's final ritual is interrupted at the last second the child may be able to choose to accept the magic, or remain as they are. at this point though they are so infused with fey magic that they are extremely likely to develop magical abilities anyway.