I very much liked the story and the world-building (definitely ideas to develop further there), and foreshadowing (if you excuse the pun) of light as a weapon (reference Archimedes Mirror Mythbusters episodes), though it seemed implied the plan was the High Elves (use of the phrase bound to), it seemed more that the executed plan/details was actually Chianna's? If I did not read that wrong, some additional focus there might have strengthened the argument portion and linked the title a bit more if you had additional word count to play with. This would make for a good longer story beat I think, and would like to see more.