A crawler missing from Porthus's own crawl, the object of his unhealthy lifelong obsession.
Rosetta loves and more than trusts Porthus — despite his unhealthy obsession with finding a missing crawler from his own crawl, named Menerva. The obsession is one of the few things about him she openly disapproves of, and one of the few subjects on which he is not simply always right.
Nothing else about Menerva is known to Rosetta beyond that she vanished from Porthus's crawl and that he has never stopped looking, an unresolved thread running underneath the whole of the Open Intellect Pacifist Network's plan.
The missing crawler Porthus has spent his life searching for.