You could tie in that Priestess wants this power so she can open a portal to Lolths Demonweb pits and as time goes on the portal gets bigger letting bigger creatures come forth. Might be nice way to introduce some interesting monsters.
You could make so that some high ranking person (even maybe...
I have a couple ideas.
The Ritual could just produce similar results of the previous one. In reality the spell not only puts the dragon into a slumber but slowly drains it lifeforce and magical essence and that power is absorbed to a high priestess of drow who slowly gains power and turns into...
I would agree with most of the posts. You should award players for creativity and it is creative way. Make your monster so it can have enough legendary resistances to counter him or give the monster advantages of saving throw. I would still make it extremely hard but possible to pull off.
So I made the translations. Not sure if every translation will work. Might change some things, but I need to test play this translation to see how it works. Hope you understand. Sadly I can not send you PM because I need atleast 5 posts in forums to do that and I don't want to just spam the...