The Ice Warriors are a reptile species who come fromthe planet Mars. They are very tall and dangerous creatures with guns on their right arm. However they do have 1 weakness and that is heat as they can only survive cold temperatures. The Ice Warriors have fought 2 carnations of the Doctor. They have tried to take over the planet Earth and the whole Galaxy. When the Doctor first met them there were a small group of them frozen in a mountain of ice along with their spaceship. Only 1 warrior was frozen until he melted the ice and freed his other warriors. They wanted to take over the Earth and make it a new Ice Warrior world. But the Doctor foiled them and killed all of the warriors in the ice mountain.
He would once again meet them and again they wanted to take over the Earth. They first attacked and took over the Moon leaving 1 human alive to operate a transmat system called T-MAT. This time we saw the first appearence of an Ice Lord. He was called Slaar. His plan was to send deadly seed pods to Earth and then send the Grand Marshalls invasion fleet to attack Earth. After they were betrayed by the human survivor he was killed. The Ice Warriors sent a troop to Earth and he managed to freeze the weather controls for the rain. Rain was what could defeat the seed pods and their deadly foam toxic poisons. The Doctor found out that the warriors on the Moon were sending a sound wave to the battle fleet to guide them to Earth. But again the Doctor ruined their plans and sent his own transmission using a satellite to guide the fleet into the sun. It worked and the invasion force was wiped out. Slaar and his remaining warriors were killed and once again Earth was saved.
The next carnation of the Doctor met the Ice Warriors again but this time they were at peace and didn't fight as they use to do. They were ambassadors for Mars at a diplomatic meeting on the planet Peladon. The Ice Warriors weren't the only diplomats representing the Galactic Federation on Peladon the others were Alpha Cenaturi who was a tall one eyed creature with six arms. Arcturus who was a head inside a glass liquid casing and the diplomat from Earth who was late. The Doctor told them he was the diplomat from Earth and that Jo was his leader. However somebody was trying to frame the Ice Warriors led by Lord Izler. When Arcturus' life support system gadget was removed Jo found it in the Ice Warrior's room. Lord Izler did tell Jo that he didn't steal the device. Later on the Ice Warrior's were believed and Izler's assisstant blew up Arcturus who was framing the Ice Warriors. Hepesh who was working with Arcturus was later killed by Aggedor. At the end of the story the Earth ambassador arrived and the deligates then knew that the Doctor wasn't who he said he was but by then the Doctor vanished.
The next time the Ice Warriors faced the Doctor again on Peladon they wented back to their own ways (well some off them did but others were at peace). Commander Azaxyr and his Ice Warrior guards were really working for Galaxy 5 who were at war with the Galactic Federation. Azaxyr and Eckersley were killing miners and guards in the tunnels and blaming it on Aggedor. The Ice Warriors needed some fuel called Trycilicate to give to Galaxy 5 to win the war. When the Ice Warriors watched the miners work the Doctor heated up the tunnels making the warriors almost faint. The warriors were then attacked and knocked out. Eventually after the Ice Warriors were killed Commander Azaxyr and 2 warriors were holding Queen Peladon as a hostage but unfortunatly Azaxyr and his warriors were killed. Eckersley tried to run for it but was killed by Aggedor. He also killed Aggedor too.
That was the last appearence of the Ice Warriors in Doctor Who even though another season with Colin Baker as the Doctor would have seen them return with Sil in "Mission to the Magnus."
They have appeared in:
Season 5: The Ice Warriors
Season 6: The Seeds of Death
Season 9: The Curse of Peladon
Season 11: The Monster of Peladon