Drills are a man's romance

This event dungeon will only drop 500 of this spellbook before ending, which should happen within 24 hours after the dungeon starts.

I was one of the lucky 500. Got it when there were ~200 left. And it wasn't easy to get - full stamina, one stamina recovery (yes I used stamina recovery for this), one level up, and 10.5 hours later, I got it when playing right after IPT (Singaporean male citizens know what it is) and right after I got 35 stamina. So IIRC total I tried ~12 times on the highest difficulty (35 stamina).

Those people who got it right at the start are extremely lucky. Also around 100 were taken up within the first 1 or 2 hours (can't remember exactly), after which the rate slowed down considerably, presumably because people were waiting for their stamina to recover. Still, all 500 gone within 24 hours is pretty fast considering the difficulty; I wonder how many people spammed stamina recovery.

While I like how the low drop rate means busy people are not at a disadvantage to those with lots of free time, the low drop rate and high stamina cost coupled with the short duration of the dungeon (due to limited quantity) means people who use lots of chocolate have a higher chance of getting it by spamming stamina recovery instead of waiting half a day for the stamina to recover. But hey it's a good business strategy.

English name: Cammie / Young Kindling Cammie
Japanese name translated to English: Kurimu-chan / Young Flame Kurimu-chan
Skill: Terminate (Increase party damage by 50% for 5 turns)
Party skill: Red Sharp Spear (Increase party Red damage by 50%)

Pretty ok stats I guess, I don't own enough 5-star spellbooks to be able to judge, but it's better than a 4-star at the very least. But is it worth the difficulty in getting? I dunno.