The following is a video transcript
Todd Kenreck: Mordenkainen's Tome of Foes not only has monsters that are horrific and disturbing but they also have ones that are alien and even endearing.
Adam Lee: With the Gray Render, you've got this crazy beast that again in the lore ... Some lore is about this thing was created through elemental forces, kind of like a Galeb Duhr or a Xorn or something like that, or the elemental powers generated this thing through its magic. Then there's other sources of lore that's a group of silver dragons were polymorphed into elves and they wanted body guards so they created these Gray Renders to be their body guards. Whatever the origin of this creature is, they have this strange sort of bonding that they do. If they meet you and they're looking for a master, they will bond to a single person and that person becomes sort of their master. And that sounds really great because Gray Renders are tough and they're super loyal and they will destroy shit at your command, however, they are also like bulls in China shop.
There's a chart for the Gray Render, it's sort of random things that they will do at any time and some are like they will just spontaneously chase birds and it doesn't matter where you are or what you're doing or if you're trying to hide from a dragon or if you're in the middle of a city square, of if you're in somebody's house, if they see a bird they will charge out and try to catch it and they'll smash their way through anything, so they'll blow your cover. Also, a Gray Render could be something like it's terribly jealous and anything that tries to get your attention it will attack, and when they attack they attack for good. They're just 0 to 100. So you kind of have this fun trade off of a story, if you want to get tangled with a Gray Render, you have this incredible bashing monster that's at your side, that's super loyal and will do your bidding.
However, you have this sort of counter productive part of it where it can totally blow your cover or it can attack your friends, or it can kind of just randomly go berserk and do wacky stuff.r. They're big, they're gray and they have six eyes, big giant fangs, huge claws. They're bulky and burly, probably the size of an ogre and they're no joke. If you're a first level character, you could run into a Gray Render and you can make a pal and you've got this awesome smashing machine that can sort of boost your ability to take out bigger, tougher foes, but it could also destroy your war horse or eat your friend. It is definitely such a cost verses pay off monster and it was a thing that you could get as a low level character and it seems really, really fun at first and then the fun really begins when it actually kinda cuts loose and does something really random and crazy.
So it was just like, this is a fun story that can be told. This is a fun thing that this creature bonds to you and it's like a way for a fighter to get a weird familiar. Wizards don't always have the fun of having their pals, their animal pals. This thing can bond to anybody but it is a bizarre creature and they're also, I don't know, they're alien. They are from a different kind of realm I guess is the way to say it. That they're not sort of mammalian or anything, they spontaneously generate sort of these little modules that pop off and then those things turn into Gray Renders and you could find a little Gray Render that's growing and you could raise it until it's eight feet tall and then it smashes stuff.