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.

Sweet street is sweet

Finally they're giving out gold-star character that isn't a Recovery type. But then it's a Strength type.

Not too shabby. First time I see the skill Infernal Waltz, wonder is it better or worse compared to Source Flame (Deals red damage each turn (ATK based)).

And also, the Revival dungeon this time, we get another sweets-related character.

 Standard stats for a 4-star, Attack Doctrine is a nice skill to have.

Finally got Rachelle

Yes the Kerras have multiplied. I continued trying to get Rachelle by playing the Lv3 dungeon. Almost gave up. After all I only got it on the forth drop.

But the drops do happen quite frequently for the Lv3 dungeon. Perhaps because there are two boss characters? On the other hand the Lv4 dungeon with the two bodyguards protecting the boss I kept getting the bodyguard's spellbooks instead. This might be one of the rare times when it is easier to farm Lv3 than Lv4. Especially with the Lv4 dungeon screwing up on the first day and the boss not appearing, just the bodyguards.

Anyway here are the stats for Kerra and Rachelle:

So much for rare spellbook from 1 hour limited dungeon

Not really what I consider to be worth the difficulty getting. So is Strength Type in general. But at least the Delay skill comes in handy sometimes and I can finally stop using Karen for it. (But Karen also has Source Flame, so hmm...)

I conclude that you cannot get Rachelle by defeating Kerrachelle

 ...after getting Kerra 5 times. 5 out of 5 is statistically significant enough for me.

Now, what do I do with all these Kerras? Make an army of Kerrachelles? It's not SuperRare but the stats are very good for a 4-star. Just need to hope that it scales well as the spellbook gains levels. Easy to evolve too (no 3x rare evo books like certain spellbooks).