Favonius Codex is a Catalyst in Genshin Impact that boosts Energy Recharge and regenerates Energy with Crit Hits! You can get the weapon via Wishes and its special effect is Windfall:
CRIT Hits have a 60% chance to generate a small amount of Elemental Particles, which will regenerate 6 Energy for the character. Can only occur once every 12s.
Builds that can use this Weapon are: