Place the deer roast in the slow cooker (crock pot). Basically, just put every ingredient in the crock pot.
Pour in the entire jar of pepperoncini peppers, including the juice. The pepperoncini pepper juice makes it a bit spicy and creates an amazing flavorful broth.
Add the entire stick of butter (sliced) and sprinkle the beef stew seasoning and ranch seasoning over the top.
Toss in the chopped onion, baby carrots, chopped celery, cubed & peeled sweet potato, peas, and garlic.
Pour in the fire-roasted tomatoes and broth.
Season with salt, red pepper flakes, and black pepper.
Cover and cook on low all day (about 8 hours).
When it is time to serve, use kitchen shears to cut the roast into bite-sized chunks. No shredding - just hearty, meaty bites in a rich, flavorful stew.