
Gacha comes from the Japanese capsule toy vending machines that give out a random prize for money, very popular with children.
A Gacha game lets you buy loot boxes which provide playable characters and gear randomly, and tend to feature a gameplay loop designed to tempt you into paying real money for those boxes.
Terrible. They are terrible today. The last game pair they put out was an absolute joke in every regard.
I recommend never giving them another penny.