This has nothing to do with the last supper. He was crucified by the Romans, but Jesus was handed over to the Romans by his own people. At that time, Roman rulers, Jews, chief priests and hundreds of thousands of centurions among Jews could not tolerate Jesus.
For those who believe in Jesus, he is the savior, because he teaches his disciples how to do things, how to be a man, bring real peace to the world, and is the embodiment of the Tao.