Ocean Adventures in D&D, Part 3 – Sea Monsters

The Player’s Handbook, Dungeon Master’s Guide, and Monster Manual all provide great resources for undersea or ocean-based D&D campaigns. We’ve offered you an Undersea Guide to the Player’s Handbook and an Undersea Guide to the Dungeons Master’s Guide. Today we’ll be talking sea monsters with the Dungeons & Dragons Monster Manual.

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This week’s post is part of the RPG Blog Carnival. This month the carnival is hosted by NukeTown.com, and the theme is “All These Worlds.” Be sure to check them out and see what others have shared on the topic.

The Monster Manual is full of useful creatures for your undersea campaign, and the easiest way to access these is to refer to appendix B in the Dungeon Master’s Guide, which lists coastal and underwater monsters. Below is a list of suggestions for expanding on those lists.

Sea monsters
Image credits: Laura College

Aquatic and Amphibious Variants

Many creatures can become sea monsters by giving them the ability to breathe underwater and a swim speed. Twig blights could become seaweed blights, while you could replace a frost giant’s greataxe with a trident and call it a sea giant. Be careful with some monster abilities though, an ocean basilisk could pose a real problem for characters who can’t breathe underwater.

Undead Creatures

Most undead creatures can survive underwater, without any modification. Adding a swim speed is usually all that’s needed to make them effective threats. Ethereal undead, such as ghosts, can use their fly speed instead of a swimming speed, making them difficult to escape.



Constructs

Similar to the undead, constructs don’t need to breathe, so giving them a swimming speed is usually enough to make them useful. A homunculus might have a swimming tail instead of wings, while golems might be formed like sharks or dolphins, giving them a swimming speed and a reduced base speed. You can also replace some golem abilities with ones from other sea monsters; like giving a flesh golem tentacle attacks to replace its slam attacks.

Common sense if your greatest ally here — a stone golem is more likely to sink than swim.

Sea monsters
Image credits: Jonas Allert

When it comes to sea monsters, a little creativity goes a long way, and the Monster Manual serves as an excellent starting point for populating your campaign world.

What’s Next?

What would you like us to cover for your undersea campaign next? Let us know in the comments below.

We recently asked about trinkets in your D&D game, and we’d love to hear your ideas, especially if you’ve got some ocean themed ones.

Till next time, play good games!

Rodney Sloan
Rising Phoenix Games

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