Slithering Overlord (Dungeon Crawl Classics 37)

The Slithering Overlord by Artem Serebrennikov, published by Goodman Games 2007 softcover. An adventures for character levels 4-6

The heroes are employed by a religious group called The Order of The Invincible Sun to recover treasure and hostages from marauding creatures. As the characters advance through winding passages of the underdeep, fighting all manner of weird creatures, they learn that the situation is far more complicated than they were led to believe. Eventually the heroes come face to face with the Slithering Overlord himself at the heart of his overgrown realm several hundred feet underground!

Remember the good old days, when adventures were underground, NPCs were there to be killed, and the finale of every dungeon was the dragon on the 20th level? Those days are back. Dungeon Crawl Classics don't waste your time with long-winded speeches, weird campaign settings, or NPCs who aren't meant to be killed. Each adventure is 100% good, solid dungeon crawl, with the monsters you know, the traps you fear, and the secret doors you know are there somewhere.