Energy Resistance

The aegis gains resist 5 against his active energy
type. This resistance increases by 5 for every 5
levels the aegis possesses, to a maximum of 15 at
10th level. This customization can be selected multiple times. Each time beyond the first, the
aegis selects an energy type (cold, electricity, fire,
or sonic) to gain resistance to, in addition to his
active energy type. If the aegis' active energy type
is the same as one he has selected, the effects do
not stack.