Does the gacha in this game have a pity system?

yes, the game has a pity system called Loyalty Points. For every summon you make using diamonds, you gain 1 loyalty point. If you use a Coupon/Ticket summon, you'll only get 0.5 loyalty point.

If you reach 100 points, you'll get a guaranteed 4*. Once you've reached 200 points, you'll get the Rare 4*.

Loyalty points are reset once the banner ends. Unused loyalty points are not carried over or converted to points for future events.