The final ritual was the Drayan death ritual, as described in their scrolls.
Drayans, in their final form as children, were brought to the Crysata, a term for one of Drayan II's moons. After that, the Morrok was said to take them away.
According to their scrolls, they ought to be happy, as when they died, the energy inside them would be set free. (VOY: "Innocence")