As fantastic as that thing would be, if anyone found any evidence of a past civilization on Mars, it would be dead as a hammer, and it would probably have died out before life on Earth ever moved out of the ocean and onto land, since the current estimates of planetary geologists indicate that Mars has been in what amounts to a global drought for about the last 600 million years.
There is, at the present time, no credible evidence of intelligent life ever having lived on Mars.
What scattered, controversial evidence exists that life of some sort might be able to exist today in places on Mars also puts severe constraints on it. If it exists, it's likely small, relatively unsophisticated and either unicellular, like bacteria, or--at most--something like lichen. The most habitable places for something to live are deep underground or beneath the ice at the poles. That rules out (nearly) all animal life (something like tardigrades would be a very, *very* remote possibility), and most plants.
The odds of life existing--today--on Mars, while not zero, are also not very high. The odds of finding sophisticated, advanced life are even moreso. The odds of finding the remains of a civilization on Mars, while again nonzero, are so remote as to beggar imagination. Finding any or all of them implies nothing about your antichrist, save that life of some sort existed somewhere other than Earth.
