I love the idea, and I love monster weaknesses that make sense and are scryable by players (like the classic of skeletons vulnerable to bludgeoning damage), but many of these weaknesses seemed silly or such a rarely occurring coincidence (if a cloud giant moves within 15' of a mold or fungus?) that they aren't useful for me. Also, the index being sorted by monster type (Aberration, etc) rather than alphabetical makes it a pain for DMs like me who can't remember exactly what type the monster we're trying to quickly look up is.

Clearly one of the best products on the DMsGuild, and highly recommended. Using this right now on an Avernus playthrough to give my players chances to learn and exploit weaknesses for devils, demons and other creatures. So good, I just bought the Monsters Weakneses of the Multiverse version.

ps: i think you are missing wyverns, guys, i can't find them in the book, but don't worry, we'll keep this between you and i

In my humble opinion, this is the single best resource on the DM's Guild.

These are some of the coolest, unique ways to spice encounters up. Rewards players thinking outside of the box and introduces more mechanics like researching monsters (in-game of course) for your party. Definitely worth picking up

This is an innovative, comprehensive, and polished book from a talented team. Surface level, the book looks amazing. Fantastic art and an organized layout parallel what you'd expect from an official D&D 5e book. Digging into the actual content reveals a treasure trove of ideas for DMs add to their games. The addition of concrete social weaknesses with mechanics to monsters is genius. We've all either had players or been the player who loves to circumvent the DMs prepared combat in favor of a social challenge instead. Also, the new combat mechanics are simple yet creative, and are a nice incentive for characters who like to research a monster beforehand. Finally, the extra touches in Monster Weaknesses make the book fun to read, like the NPC experts introducing each classification of monster. This is an excellent purchase.