Portals inside Einstein's Portal are powered by resources called Antimatter, which are crucial in determining the heroes you can summon. Here's how it works:
Regular Antimatter: Mostly yields 2 or 3-star heroes, with a small chance of getting a 4-star hero and a slight chance of a 5-star hero. After a certain number of pulls, a 5-star hero is guaranteed. After a certain number of pulls, you're guaranteed a 5-star hero.
Legendary Antimatter: Guarantees either a 4-star or 5-star hero, giving you access to the game's most powerful characters.
Event-specific Antimatter: Such as ChineseAntimatter, offers an increased chance of obtaining specific heroes tied to the event's theme. For detailed probabilities and specific hero chances, tap the information tooltip in the game.