Krishna does not tell Arjuna that after liberation, after their covering of illusion is removed, either Arjuna or any of the kings will cease to exist. Individuality of the soul is eternal, that is what Krishna is telling Arjuna here. But after moksha or liberation, the individual soul becomes one with the Supreme in his purpose - he does not do anything that is not in connection with the Supreme. Krishna or God's name is asamurdhva which means nobody is either equal to or greater than God. This is not my philosophy but it is the same timeless philosophy enunciated by all great teachers down the ages - Sri Ramanajacharya, Sri Madhvahcarya, Sri Vishnuswami, Sri Nimbarkacharya and even for that matter Jesus Christ, though he did it in ways suitable to the particular situation and circumstances where he appeared.
