In our last posts we've been discussing different types of disguises: those that attempt to hide one's true self and those that reveal it. We saw how various Narnian heroes attempted to disguise themselves into things they were not and were either stopped from doing so, or the disguise utterly failed. Tumnus, however, unknowingly disguised himself as one who was going Christmas shopping. And because this revealed his true nature as one hoping for Aslan's redemption, he succeeded in playing a role in that redemption.
The reason for this is that any true hero, and any true redemption, cannot come without one's true self. There is no hiding! Queen Esther had to reveal that she was a Jewess to bring about redemption, she could no longer hide. So too, Peter and the Pevensies and Shasta and Aravis, could not hide as slaves or merchants to achieve their personal redemption. They had to be themselves.
In the Last Battle both villains and heroes attempt to disguise themselves. First, and most importantly, Puzzle is convinced to disguise himself as Aslan. In this, Puzzle made no attempt at redemption or anything else. There was no plan, no goal, and certainly no redemption in Puzzle's mind. Quite the opposite, there was an anti-redemption, a false redemption in which Shift perceived the redemption of Narnia in the Calormen Empire and not in Aslan. And, indeed, it worked. A false redemption can occur, in fact it must occur, via lies and untruths.
Furthermore, a false redemption must be totally false. Shift attempts to disguise himself as a man and a king by putting on Tirian's crown. And, in a sense, he succeeds. The Narnaians call him a man and worship him. It is only we, looking from the worldview of true redemption, and the Calormens who are making no attempt at redemption who are no fooled by Shift's disguise.
Finally, we have our heroes, Tirian, Jill, and Eustace, once again dressing up not as their true selves, but as Calormens. And while they have some temporary success, their ultimate failure is never in doubt. In fact, it is as Calormens that they see Tash himself has invaded Narnia. The fight cannot be one as someone else.
Those who truly seek redemption can never be ashamed of their hopes and dreams. Though tempting such disguises cannot work. The disguises one should wear are those that further the redemptive cause, to act as heroes even if we are not and to dress up, to be, great warriors of God even if we don't recognize it when we look in the mirror. God chooses the method of redemption, not us. Our job is to keep His banner raised high.