The Ore of Dark Crystal

Lately I've been conducting some secret, discreet checks without anyone else's knowledge. We have a problem where the saintly dolls have turned into ruthless monsters. What happened?

No one knows why, and the situation is getting worse by the day. What is going on there? Is it the act of an alien? Or something else? All I know is, I can't leave this post because I'm the general. Please help me take care of other things.

Okay, then! Since these previously-friendly 兔子鼓手 have turned into menacing monsters by an unknown power, It's up to you to investigate them.

Defeat the 兔子鼓手, a monster featured at the 67th floor of Eos Tower, and you'll sometimes find an item called 暗沉水晶. Hardly anyone knows what to do with it, but I think it's a very important item. Inside that item lie the clues to the case.

Please go to the Eos Tower in place of me, defeat 兔子鼓手, and collect 20 暗沉水晶s for me. It's doesn't seem like an easy item to obtain, but I'm sure you can collect it over time.

I thought I could count on you to take care of this mission, but I guess not. This is a discreet project, one that cannot be advertised to total strangers, so... if you ever change your mind about this, then please talk to me, okay?

Are you finally back now? Let's see the items I requested... Hoh... very nice, and trustworthy! Alright, there's no way I am not going to give you a reward. Take this first, and... I'll slowly explain everything about 暗沉水晶.

Alright, let's see... Hmmm... Just as I thought. Were you aware of this? Drumming Bunnies were supposed to be the adorable party-starters at the festival in Ludibrium. They were the ones that made the festival fun.

And then, one by one, they started turning into monsters. I had a hunch that this crystal has something to do with it, and I'm afraid I'm right on this. It's not enough, though. I'll need to study this from different angles, so I can find out exactly what happened in the first place.

Anyway, I can't thank you enough for your hard work here, but the crime hasn't been solved, yet. We were able to find an important clue towards solving the crime, but we haven't solved it yet. I'll try to figure it out, but I am pretty sure I may need your help down the road. Please drop by whenever you have time. I'll see you around.

Hmmm... I don't think you've gathered up all the items I was asking for. I really think there's a correlation between the previously-gentle dolls suddenly becoming monsters in rage, and an item called 暗沉水晶. Please head to the 60th floor of the Eos Tower, defeat 兔子鼓手, and then collect 20 暗沉水晶s for me.