The Lagoon trait, freshly introduced in set 7.5, has a built-in loot system that depends on the amount of casts from champions with the Lagoon trait!
Breakpoints are 3/6/9/12, with each granting extra ability power and attack speed to Lagoon troops. Malphite, Taliyah, Kai'Sa, Zac, Seraphine, Zeri, Nilah, and Sohm are the only TFT Set 7.5 champions with the Lagoon attribute.
The amount of casts from Lagoon Set 7.5 champions determines loot awards. While the prizes are constant, consumables such as Blue Buff and Radiant Blue Buff can boost the overall number of casts throughout the duration of a game. Above the Seastone on the board, a count of casting from Lagoon champions is also available to see.
According to Mortdog, Riot's design director, all prizes over 750 casts are item components, with the exception of one mystery treasure item.
The more Lagoon troops a player runs in a competition, the sooner those units achieve greater rewards. Loot in the Lagoon trait is fixed and will not ever change.
Kai'Sa, Zeri, Nilah, and Sohm are champions who can carry games with the Lagoon trait. Kai'Sa is a reroll combo that combines Lagoon and Dragonmancer. It's a solid early-game build with the potential to last until the late game. Players will want to give Kai'Sa a Blue Buff to increase the number of her casts and chances to get more loot from the Lagoon trait.
Nilah is a formidable four-cost carry who can speed up her spells with a Blue Buff or Radiant Blue Buff. Nilah can also equip the Jeweled Gauntlet and the Infinity Edge. And, using a brand-new champion inside TFT, Sohm is the tier-four dragon for the Lagoon trait. Sohm works well with Mage units and uses Blue Buff to speed up his spells.