@ fffffplayer: My apoligies, my posts have been edited. I did not intend any offense.
@ Strider: Yes, I got Breath of the Wild the day it came out. :D (More acurately, actually, my brother got the game for me as a late birthday present the day it came out. :P) Unfortunately, due to school and such, I have not gotten a chance to play it much, so I have been very carefully secluding myself from spoilers about the plot until I do get a chance to play it. I actually haven't gotten to the part of the game in which these songs appear. To the best of my knowledge, the Hyrule Castle song plays as you infiltrate the captured Hyrule Castle which is teeming with all of the most dangerous enemies so you can face off against the final boss, so I would defnately say that its tone is "dangerous." Beast Ganon is the final boss, and the two Beast Ganon themes play during the fight against him. Listening to the music just serves to hype me up even more for when I finally do get a chance to play that part of the game. :P
From what I've played of the game so far, it is absolutely increadible. I would go so far as to say that it is the best single player game ever created in the history of anything. :P I would definately recomend you get it, though you'd have to have a Wii U or Switch, so it might not be possible for you to do that. :( Luckily I had a Wii U already so I was all set, but if I hadn't had one, I probably would have bought a Switch just for Breath of the Wild alone. :P Yes, I am obsessed with that game. :P