Whenever you add a card that gains Block to your Deck, Enchant it with Nimble 2.
Fresnel Lens currently ranks #7 out of 292 in the Slay the Spire 2 Relics tier list with a rating of 1632.40.
This ranking is based on 27 community votes (23 wins, 4 losses) for a win rate of 85.2%.