Iron Woobie: Arguably, Michael O'Neal, Jr. by the end of the Posleen invasion. As far as he knows, his entire family (save one daughter, raised by aliens and becoming more like them every day) has been killed, two of them in a choice from hell at his order to save North America, and all that's left to him is a military service whose financiers are trying to shoot it in the foot at every turn. How can you not feel for the guy? Things really don't get better for him until Eye of the Storm.
Magnificent Bastard: Tulo'stenaloor, the primary antagonist of the two-parterWhen The Devil Dances and Hell's Faire. Unlike most Posleen kessentai, or "God-Kings" as the humans call them, Tulo'stenaloor takes many concepts from his human foes, allowing him to spy on his opponents, recruit similarly intelligent and gifted kessentai while tricking more traditional kessentai into being cannon fodder, and use the very type of air support that the Posleen deny the humans. While technically the advisor of Orostan, the Posleen warlord in charge of a massive staging area in what used to be Clarksville, Georgia, Tulo'stenaloor manages to prove that he is the Evil Counterpart of Mike O'Neal, Jr. While O'Neal is excellent at killing Posleen, Tulo'stenaloor, who actually left the planet where O'Neal became famous, adopted and adapted human tactics to outmaneuver and outsmart his unsuspecting foes.