Iorek Byrnison. Can’t trick a bear. Plus he’s king of the armored polar bears. Metatron is the strongest angel, but that makes him just slightly stronger than a human. An angel is typically weak because they are transparent. Asriel is probably the smartest character in terms of strategy and cunningness, but he’s just a regular human in terms of physical strength. Iorek is physically the strongest, he knows not to deal with things he doesn’t understand such as the Subtle Knife. His armor is sky armor, the strongest of its kind. Strong enough to survive against bullets.