I suppose this conversation would sound odd if you weren't from our world - Solona and I are Grey Wardens, at home. In order to become one, you take on a corruption or taint in your blood that changes you, in some ways. It allows us to be more effective in killing Darkspawn, and allows us to dispatch their leader (an Archdemon) if one should arise. But it also shortens our lifespan, and makes it so that we're likely to turn into one of their own after some.. odd amount of years. No one's been quite sure about that one.