Champions in Riot Games’ new autobatter, Teamfight Tactics, are divided by Class, Origin, star, and cost. The higher the star, the stronger your champion. Once you reach three stars, your champion has been fully upgraded.
It requires nine of the same champion to upgrade to three stars. With each star, the champion’s stats are increased and its ultimate ability is improved. In the case of some champions, it makes a huge difference, but with others, it’s not a deal-breaker. At the end of the game, though, you should be aiming to upgrade all of your units to three stars. It’s not always possible, and it entirely depends on your army, but it should be your end-game goal.
The early game is the best time to accumulate early three-star champions. From levels one to four, the one-cost champion pool is the highest. There’s 39 of each one-cost champion. This number changes as the game progresses. After level four, the chance of receiving those champions is decreased. This means it’ll gradually be harder to upgrade your early game champions to three stars. There’s still a chance and you shouldn’t give up, but instead, it’s more intelligent to focus on mid-to-late game champions.
When you have three one-star champions, they’ll automatically combine together and create a two-star champion. The same goes for three-star champions. Once you have two two-star champions on either the battlefield or the bench, and you buy three additionally one stars, they’ll create a three-star unit.