Heat venison in skillet until browned on all sides, over low heat. Set aside.
Add chopped celery, carrots, onion, and pepper to the skillet with some oil. Go for about 10 minutes over low.
Transfer veggies and venison to a Dutch oven along with diced potatoes and barley.
Add stock and water and stir to combine. Simmer on low, covered, for 2-3 hours.
Give it a taste and add salt and pepper as desired.
Notes
Use any red meat here, whether it's wild game or beef.
Leftovers taste even better, in my opinion! Store them in the fridge, covered. The barley will continue to soak up the liquid so you might need to add more broth when reheating.