Hi Gabriel,
I think the music you wrote for the boss's appearance is very foreboding and full of dread.
The actual attack music is quicker, with more motion. It is not quite at the top of the possible spectrum of intensity, but I am assuming you are saving the most intense moments for later.
I looked up what "ailing" meant and I am not sure of the way you are using the word. The definition of ailing is "in poor health". Do you mean that this boss is almost dead at this point in the game/music? If that is your intent, then I think the music does a good job of portraying the boss as not particularly formidable. Or maybe you simply intended the music to remain in the background instead of distracting the player away from the game? But I think you can certainly increase the intensity of the music while still allowing the music to serve its purpose well as background music to this boss battle.
Thanks for sharing!
Peter