as I understand the maximum level of 11 made strictly from those considerations that you have not received all the perks in all three branches for 12 brothers and not become unkillable machines of war. It is also obvious that the 11 level and the tree of perks waiting for changes with the introduction of goblins and with the further development of the game. You not the first who would like to develop their beautiful tramps in the mighty knights continue after level 11, but still. Don’t worry – soon we will all have a new game with new enemies and new mechanics – will be what to do :)