Defensive magic: Geodshield

You told the commander that you'd prepared well for your role in serving the saintesses– and protecting your own life besides– by mastering defensive magics, among them Geodshield, capable of fortifying one's armor against lethal blows.

"It is only logical, Squire Lavender. In the case of the saintesses, you are charged with their care, a task of utmost importance. However, you may find yourself more in need of the spellcraft to preserve your own life. The demon lord's army will find you a more **** target than our lady heroes, to be sure. Now tell me: do you remember the weaknesses of defensive magic?"

You told him that the biggest impediment is the concentration involved. It would be impossible to attack while maintaining Geodshield, at least for you. Therefore, in battle, one must work as a team to defend while others do the attacking. When surrounded by enemies and without allies, all you would do is delay your own defeat and exhaust your magic ability by casting the shield.

"Exactly. The best planning is accompanied by action and the best defense is accompanied by offense. Never forget that." The commander rubbed his chin thoughtfully. "And never forget that your safety as a squire is as important as that of the saintesses when it comes to the success of Geod's design."