Board Thread:Questions and Answers/@comment-33581467-20171106141910/@comment-39140096-20190822050103

Nantoniums in NM of regardless on any drop, offers a 5% chance to being a key. However if dropped by a Savage Devastator Elite/Savage Necrosis Elite, they have a chance to drop a core(5% up to 15% on Sav. Necro). It's hard to obtain keys but it's extremely easy to find Black Boxes considering most rewards in event has one Black Box, and NM games has a small chance similar to Keys to be dropped from a secret room OR boss itself.