As long as there are four or more lore counters among Sagas you control, Tom Bombadil has hexproof (This permanent can't be the target of spells or abilities your opponents control.)
and indestructible (Effects that say "destroy" don't destroy that permanent. An indestructible creature can't be destroyed by damage.)
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.