grey renders

[van luke]

How long do grey renders live for?

[Mike Miller]

Until a ravaging band of adventurers slays them all.

[Goaty14]

For as long as the plot dictates.

[Luccan]

They only produce one offspring at a time, though when and how long it takes is unclear. I would choose a time frame for that, then choose a lifespan letting them produce enough offspring to maintain a small population (considering they live in marshes and are solitary, the territory of a single individual is probably quite large).

Of course, it's possible to interpret their fluff text as producing one offspring, period, in which case it doesn't matter how long they live, they'll probably all be wiped out soon.

[Thurbane]

As a random point of reference, give them the lifespan of an African Elephant? Maybe 60-70 years?

Or a Black Rhino: 35-50 years?

I don't think there will be a RAW answer for this anywhere, except maybe an Ecology of the Grey Render article...

Here's a link to some home-brew (I hope, site is blocked at my work for some reason): http://www.enworld.org/forum/showthread.php?219823-THE-ECOLOGY-OF-THE-GRAY-RENDER-(unpublished-Dragon-article)

here's a local one: http://www.giantitp.com/forums/showthread.php?267823-Ecology-of-the-Gray-Render

[Luccan]

Alternatively, since they bond to various creatures, you could have them not have a set life span. A grey render lives until its charge(s) die(s); it's a magical beast, so it doesn't have to work on normal physiological rules. Maybe one that doesn't bond to a group lives long enough to produce and care for a single offspring, until that offspring can care for itself.