I will start this topic in order of what I believe is simpler to implement and onwards to the more complicated stuff.
1. Warhound commands
You should be able to have a trained warhound which follows basic commands. The commands are to prioritize a target, or to stay where it is. You can buy an already trained warhound, which is more expensive, or maybe have one of your warhounds receive training in a kennel.
2. Traps
Characters should be able to set up traps, specially archers. They’re useful so that the archer won’t need to keep running away if enemies catch up with him, or also to protect his back. You can have something like a bear trap on the ground, which inflicts damage and keeps them where they are unless they have a friend to help, and also have a throwing net sort of trap which you can place next to a tree. There are other traps which could be developed, but these are the first which come to my mind. In addition, characters with a hability in the skill tree or a +vision trace would be able to detect traps when they’re close to them.
3. Cats
This is explored in many old myths and referenced to in modern culture, but cats have a relationship with the supernatural. Cats could be a more fragile pet, harder to obtain but having special skills. The main one I can think of is that a cat could ward off (they will avoid coming within 1 tile range) a particular kind of enemy, like the Alp or the Schrat.