Fairy Mimyu:
Alright. Here's the mission. Hunt the Kerberos Leger, Kerberos Fort, Kerberos Nero, Fury Sylph Barrena, Fury Sylph Labido, Fury Sylph Purka, Fury Kerberos Leger, and the Fury Kerberos Nero, and collect their Mutated Spirit's Souls as proof.
You can get rewards only if you bring at least 100. Of course, you'll get more rewards if you bring more.