who or what was responsible for its design?
The Germans.
SMS Baden
Design work on the "Bayern" class began in 1910 in the context of the Anglo-German naval arms race, with initial discussions focused on the caliber of the main battery; previous German battleships had carried guns,
what is sms baden? It was a dreadnought battleship.
wiki:5031737
SMS Baden [SEP] Design
Design work on the "Bayern" class began in 1910 in the context of the Anglo-German naval arms race, with initial discussions focused on the caliber of the main battery; previous German battleships had carried guns, but as foreign navies adopted and weapons, the German naval command felt the need to respond with larger guns of their own. They considered , , and guns. Admiral Alfred von Tirpitz, the State Secretary of the "Reichsmarineamt" (Imperial Naval Office), was able to use public outcry over the Agadir Crisis to pressure the "Reichstag" (Imperial Diet) into appropriating additional funds for the "Kaiserliche Marine" (Imperial Navy) to offset the additional cost of the larger weapons.