Hydroloth (MToF)
Yet another entry into the Fearsome Frog Folder. The Hydroloth is an amphibious Yugoloth that lives in the memory draining River Styx, and like the river, they have the ability to rob their victims of their very memories.
Being Yugoloths, Hydroloths are often hired for their aquatic assault acumen. Be it scuttling ships from below, raiding coastal settlements from the shore, or even just diving for sunken treasure. You may also find use for them if you need some pesky memories removed. In fact, these creatures give you a perfect excuse to start a mid level campaign in-media-res with a fight against them. Give the PCs amnesia (Players are often willing to make up such characters without DM prodding, so you would be surprised how many will jump at the opportunity) and give each of them patchy clues as to who they are, where they are from, and what they are questing for in the first place.
When used in combat, the Hydroloth loves to be in the water (unlike those Firenewts~!) where it has an innate advantage on all attack rolls. And like all of the better spellcasters in this book, Its three-pronged multiattack can swap out an attack for a spell. Control Water will make a slightly damp arena into a pool, or create a whirlpool in existing water, punishing any characters who used STR as a dump stat. I am going to point out the Crown of Madness spell, mostly because I honestly didn’t expect any creature in this book to have it, given how much the writers have done to avoid the word “madness” up to this point. There are other staples like Darkness (which combos well with their Hydroloths Blindsight), Dispel Magic, and Suggestion, to sell their roles as melee controllers. And should their swim speed fail to be sufficient, they can even teleport up to 60 as an action.
The Hydroloths signature power, Steal Memory, is a doozy. The target must make an INT save (The most popular Dump Stat), or else they lose all of their proficiencies, can't cast spells, and have their INT and CHA set to 5 for 24 hours. The saving throw against this effect is once per day. Nasty stuff. Of course, if you are going to use the campaign idea above, it’s best to handwave the power a bit to fit the story. It could even be a plot point: Whatever kind of magic prevents the total loss of memories, also prevents them from regaining all of them.
In the changeover, the Hydroloth had their attacks changed to force damage due to the loss of the Magic Weapons ability, and also had a psychic damage rider put on their attacks to even out the DPR for the CR. Surprisingly, they already had the ability to use a spell when multiattacking, but lost access to the Water Walk and Phantasmal Killer spells anyway.
