Each gacha is programmed to pull certain characters or rewards. To sweeten the pot, many titles will guarantee certain rewards based on the number of pulls the player does. I recently tried the mobile game Arknights, where the very first gacha guaranteed a six-star (or highest rarity) character by simply doing it 10 times. The distinction between gacha and lootbox pulls is that a gacha will always unlock something permanently for the player, while lootboxes are more about consumable resources.