Turning a Fantastic Beast into an actual beast in Dungeons & Dragons is something you have to be wary of. This is something I’ve dwelled on in the past. A ‘beast’ in D&D is commonly a ‘real world’ sort of animal, or adjacent to a very normal, vanilla animal. So most Fantastic Beasts don’t fit that category. Some are more ‘fey’-like, some more fiendish, some are ‘monstrosities’. Dragons are, well, ‘dragons’.
The reason you have to be careful is that there are spells, abilities and moves that allow ‘beasts’ to be used by the players. Magical versions can be summoned, weak beasts can be familiars, druids can morph into them.
The sea serpent is one such Fantastic Beast that fits the ‘beast’ category, but is a very big addition, and pretty strong with it. Nevertheless, I kind of like this option being added to the selection. The number of sea beasts in D&D is on the more limited side, and it’s so strong that it actually avoids most opportunities to be used by the adventurers.
If your adventurers are at sea, or on a big body of water, the casters can use polymorph to turn someone into a sea serpent (providing they are level 5 or higher). A very high-level Moon Druid (level 18+) can wild shape into this mighty form. It might feel overpowered to create something so large. You should know that the same characters could transform into a brontosaurus at the same levels, as well as giant sharks and giant crocodiles, so we’re not rocking the boat here.
The sea serpent is rocking the boat though. Oh my, imagine the villainous pirates in shock as they watch the boat they were attacking summon a 100 foot beast as their guardian.
The most interesting thing about these creatures, in turns of inventing scenarios for them, is that they are actually non-aggressive. No humans are known to have been harmed by these gargantuan serpents. Which means that, when the adventurers see this thing on the open seas, it will only attack if they panic and attack first. Or if the serpent has a very good reason to be angry, which careful players might be able to fix, and avoid the sea beasts wrath.
Thank You For Reading
All the D&D monsters made from Fantastic Beasts are right here!