Wake up everyone! Latest Zatch Bell 2 chaper has dropped! Momon has come through and reunited with Elle 凉 Not to mention Barry has now returned too.. I don't think the books and the numbers of mummies are the same, since Tio and Kanchome aren't dead but received books. There's also one left in Egypt for Kiyo's assistant, Zahara. I can see the one on the bottom right next to Zatch's being Momon, seeing as it has rabbit ears.
For Koruru specifically, maybe because she doesn't have any attack spell at all (or any debuff spell like momon's) that will help her burn opponents' books. Although yea, this doesn't explain why it has to be berserk mode. The short answer is always Plot demand, but it doesn't help.. List of Zatch Bell! characters The principle characters of the series. On the right is the titular character Zatch Bell in front of Kiyo Takamine. From the upper left clockwise: Tia with Megumi Oumi, Kanchomé behind Parco Folgore, Ponygon with Kafk Sunbeam, and Brago with Sherry Belmont.