An enemy will almost be never anything except an enemy. All one can do with an enemy is defeat him. But adversary can sometimes become an ally. There is a cost, of course. In all things in life there is a cost. In dealing with an adversary, sometimes the cost paid in power or position. Sometimes the cost is greater. Sometimes the risk is one's future, or even one's life. But in all such situations, the calculation is straightforward: whether the potential gain is worth the potential loss. And the warrior must never forget that he and his adversary are not the only ones in that equation. Sometimes, all the universe may hang in the balance.

Star Wars: Thrawn