Preheat grill according to manufacturer's directions. Remember it's always best to have a hot side of the grill where the burgers will sit 1–2 minutes on each side, and then a cool side of the grill where less intense heat will provide a place for finishing the burgers without burning. In a large bowl, place ground boar. Remove skin from brats and add to the boar. Using tip of your fingers, break sausage into pieces that resemble ground meat. Chop 3 large chipotle peppers and add to meat mixture along with 1 tablespoon adobo sauce. Add minced garlic and season lightly with salt, black pepper and granulated garlic. Using your fingers, blend meat and seasonings thoroughly, being careful not to over-mix. NOTE: Over mixing can create a tough burger. I always like to test seasoning of my burgers by forming a small nickel-sized patty and quickly sauteing in a skillet to taste for flavor. Adjust seasoning if necessary. Form 6–8 patties, 1/2–3/4 inch thick. Prior to cooking, prepare buns, fixings and relish so that burger patties do not get cool after grilling. Burgers are best served hot. To make caramelized onion relish, combine butter and olive oil in a large sauté pan over medium-high heat. Add thinly sliced onions, stirring constantly. NOTE: Make sure onions are no more than 1/8-inch thick, otherwise it will be too large for a relish and will take longer to cook. Cook onions until soft and lightly browned, about 10 minutes. The heat should be high enough to soften onions quickly but not burn butter. When onions are soft, add cane syrup and beer, increase heat to high and bring to a rolling boil. Reduce heat to simmer and cook until relish consistency is achieved, 8–10 minutes. Do not scorch. Season lightly with salt and pepper. Remove from heat and keep warm. When ready to cook burgers, oil grill rack then grill patties on hot side of pit, covered, for 4 minutes, turning at the 2 minutes intervals. Remove burgers to the cool side of the pit for another 2 minutes, turning once to guarantee doneness. Top with favorite cheese at this time if you wish. To assemble burger, coat each side of buns with mayo and a touch of Creole mustard then layer with lettuce and tomatoes. Season tomatoes lightly with salt and pepper. Add meat and top with a portion of caramelized onion relish.