Devuan came into being after a rebellion by a self-described “Veteran Unix Admin collective” argued that Debian had betrayed its roots and was becoming too desktop-oriented. The item to which they objected most vigorously was the inclusion of the systemd bootloader. The rebels therefore decided to fork Debian and “preserve Init freedom”.
The group renamed itself and its distribution “Devuan” and got work, promising a fork that looked, felt, and quacked like Debian in all regards other than imposing systemd as the default Init option.