Serra, first Muse

As long as there are four or more lore
counters among Sagas you control,
Tom Bombadil has hexproof and indestructible.

Whenever the final chapter ability of a
Saga you control resolves, reveal cards from the
top of your library until you reveal a Saga card.
Put that card onto the battlefield and the rest
on the bottom of your library in a random order.
This ability triggers only once each turn.