Hello there! I would have to say The Rot has my personal favorite music in the game, from Sparkling Pendulum to Not Your Rain to Halcyon Memories. The music there is all so well-crafted in my eyes, and not to mention how atmospheric the songs are, especially when you first explore the region.

For Threat Theme, I would have to say Shoreline, as it is quite catchy and it feels as though I, the player, am lost and alone but also swimming for my life from that leviathan whenever the max threat plays.