First of all I have to say that usually event girls are very achievable even without spending kobans - since I started playing I pretty much got every event girl (including revival events) within the time frame of the event without spending any kobans. Generally it takes roughly one week to get both, sometimes less, sometimes more.  So as usual I played the first day and regularly farmed dark lord, now that time got short I used kobans to buy refills for the very first time - luckily I amas