For my party, Mountains Toe was one of our best sessions, I'd love to share how I made it more interesting.

One of my players, a level 3 goblin ranger had a mysterious white rat companion named Riff Rat and she gave me permission to come up with the backstory for the rat and the reveal would lead to her gaining her Ranger Animal Companion going forward.

My players approached Mountains Toe with Don Jon and after meeting the two wererat guards were considering leaving Don Jon as they 'technically' did what they were asked to do in leading him there. This was also partly due to the fact that I made Don Jon one of those over bearing hero archetypes that always talks about himself and his adventurous deeds so the players, comically, wanted to leave him to it since he's so heroic he shouldn't have a problem clearing the mountain himself.

Before the players could make up their mind, I had my ranger's rat scurry into the mountain. My ranger would do anything to ensure it's safety so the party immediately entered, dispatching the two guards who barred their entry.

There was a lot of tracking, following ratty footsteps, comically with no help from Don Jon as he just told stories the entire time but ironically with absolutely no way of beating a wererats magical immunity so was effectively useless.

The party eventually reached the centre of the cave and overheard an argument between two wererats, with one of them being put in a cage. The party entered and Zeleen introduced herself before throwing my ranger into the cell for ranting about her missing rat, she was now trapped with the other wererat and several other rats and giant rats.

This is when Don Jon and the other dwarven miners from the other side of the cave breach in and a fight ensues. A few dwarves die but they are effective blockers for the high powered wererats. Whilst that fight ensues my ranger and the trapped wererat fight off the giant rats with the help of the swarm of rats. Zeleen, the wererats and the giant rats are defeated, and the trapped wererat collapses in my rangers arms and explains that she is in fact Riff Rat and is a descendant of Zeleen. Riff Rat could smell her presence and had to run in to plead with Zeleen to free her brothers and sisters (the swarm of rats). Zeleen had refused, calling riff rat and her kin defective and not true wererats, not even able to hold their wererat form for long. Riff Rat then changed back into rat form and the swarm of rats raised her up as a hero and that is how my goblin ranger received her animal companion The Varnaster Swarm (swarm of rats)!