Make the marinade by combining the soy sauce, juice of 1 lemon, banana ketchup, salt, and ground black pepper in a bowl. Stir to mix.
Put the chicken leg quarters inside a large freezer bag, and then pour-in the marinade.
Shake the bag gently to coat the chicken with marinade then remove the air inside the bag. Seal the bag then refrigerate overnight.
Remove the chicken from the bag and transfer the remaining marinade to a bowl.
Heat-up your grill and start grilling the chicken under medium heat for 12 to 15 minutes per side or until the chicken is completely cooked. Do not forget to baste the chicken with the remaining marinade mixture.
Remove from the grill and transfer to a serving plate. Serve with steamed rice.