The Admiral Class were designed as battlecruisers. After the Battle of Jutland, the deign was changed to allow more armor to deal with plunging fire. With this change, one could call HMS Hood a fast battleship, whereas the Renown and Repulse were obvious battlecruisers. However, Bismark had more armor. More importantly, it didn’t have torpedoes and had more modern range finding equipment. HMS Prince of Wales and Bismark survived hits with relatively little damage. Hood blew up like so many earlier battlecruisers had at Jutland.
And yet, to this day, no one is quite sure why Hood sunk. They’ve even now explored the wreck and they still don’t know why. The logical explanation is that she took a hit in the magazine and blew up. The only problem is: None of the witnesses at the time remember hearing or seeing an explosion.