Not in the specifications. They just say, ‘anyone who breaks the Vow dies.’ Ending with death is a feature.
Though if the people who first found the spell really thought that way, they must not have truly believed anyone could stay in their world after death.
But will they come back free of the Vow? It seems entirely plausible to me that it would follow them into their new incarnation.
They could still break it once per incarnation.
… thus killing one human per incarnation, thus creating one horcrux per incarnation.
Now, if there were some way to automate the whole getting-a-body-business …
Not in the specifications. They just say, ‘anyone who breaks the Vow dies.’ Ending with death is a feature.
Though if the people who first found the spell really thought that way, they must not have truly believed anyone could stay in their world after death.