Kipling was a staunch imperialist seeing it as ''the White Man's Burden'
Daniel and Peachey represent the Empire expanding to the benefit of the natives. The 'White man's magic' of course impresses the credulous natives, and they reap the benefits of their modernity by ruling.
It is only when they start familiarising with the locals that their prestige is destroyed.
Kipling is warning to keep them at arms length, and stay with your own.
The antagonist is always the person (or people) who oppose the protagonist, so the antagonist would try to take down or stop the protagonist from achieving his/her goals
D she tried to commit suicide
The word realm could mean a type of dimension or a specific place.