In a skillet over medium heat, cook the Italian sausage until browned and crumbled. Drain any excess grease.
In a large mixing bowl, combine the cooked sausage, sliced pepperoni, mozzarella cheese, diced bell peppers, diced onion, marinara sauce, Italian seasoning, garlic powder, salt, and pepper. Mix well.
Unroll one can of the crescent roll dough and press it into the bottom of a greased 9x13-inch baking dish, making sure to cover the bottom and up the sides slightly.
Spoon the meat and cheese mixture evenly over the crescent roll base.
Unroll the second can of crescent roll dough and place it over the filling, sealing the edges by pinching them closed.
Bake in the preheated oven for 25-30 minutes or until the top is golden brown and the filling is bubbly.
Once baked, remove from the oven and let it cool for a few minutes before slicing.