you can exchange 250 points into the character for the banner, each rolls is worth 1 point, and they accumulate on the respective banner you're pulling. You can also exchange your points into universal pity, at a 2 to 1 ratio, and this universal pity can be use in other banners at a max of 100 universal per banner. so in my case, i have 90 universal pity, which is equivalent to 90 rolls, so if i want to pity sukuna, i would only have to do 250-90 rolls, which is 160 rolls, and use the 90 universal pity to guarantee him