OpenBSD

Secure by Default
OpenBSD's motto is antagonistic to the mainstream "User-friendly first, and security be damned" approach that has driven software development elsewhere.

Only Two Remote Exploits in the Default Installation, In Over Ten Years
This motto has been true since 2006.

OpenBSD's baby roots in NetBSD
OpenBSD does have baby roots in NetBSD. It is maybe because Theo de Raadt had broken away from NetBSD and started OpenBSD, the Secure By Default BSD.