Talk:Spring 2015 Event/@comment-84.90.161.45-20150510171234/@comment-26082284-20150510192509

It's probability. If chance of Roma dropping is 1.3% per S rank (as some sources suggest), then your accumulated chance of obtaining her in 100 sorties is about 73% (if I did my calculations right). That means out of 100 TTKs farming K node, 27 won't get her in 100 sorties. Apparently, you're one of those poor souls.

Bad luck, in other words.

Don't give up. While probabilyty of her dropping will never be 100%, every try might be the winning one.