Gerton, Scion of Lage

{s},{t}, sacrifice a creature: put a ritual counter
on Gerton, Scion of Lage
{s}, remove a ritual counter from Gerton: add
{b}{b}{b}
{s}{s}{s}{s}{s}, remove 5 ritual counters from Gerton: create Marit Lage, a 20/20 legendary avatar creature token with flying and indestructible