The Blue Spine Shield is the best shield in Lunar Knights not only due to it's defensive capabilities, but also its special ability. Its unique property is that each successful counter, a portion of the enemy’s life is rebounded back at them. Furthermore, this shield can only be obtained on Hard Mode, which requires a previous play through of Lunar Knights to access. It can be obtained in the Dark Castle Auguste, at the location where Aaron and Lucian split up, you must take Aaron's path which will lead to the Blue Spine Shield.