Children of the Divine Order
Defense magic is all about personal defense and protecting one from harm. For most uses defense can only protect a single person, very strong wielders of defense have been known to create defensive shields over small areas to shield more than one person.
Defense magic is not terribly useful at overcoming challenges. However at times people have come up with creative ways to use defense to overcome obstacles like being able to walk through a fire.
Create an Advantage
Defense magic can be used to create certain advantages. Most of these are personal advantages like temporary resistance/immunity to a certain form of damage. A creative person may be able to come up with other ways of using it to create advantages.
Defense magic is not suitable for attacking.
Defense magic is best at defense as the name implies. It can either directly be used as a shield or act as armor.