Souls

Souls are not affected by gravity and thus stay floating where they are dropped. They are dropped by certain enemies in hardmode. Soul of Flight is dropped by Wyverns, Soul of Sight by The Twins, Soul of Light* by enemies in the underground area of The Hallow (namely the underground portions), such as Chaos Elemental, Soul of Night* is dropped by enemies in the underground area of The Corruption. Soul of Fright is dropped by Skeletron Prime, and might is dropped by The Destroyer.


 * Oddly enough, it has been observed that certain enemies will drop both Lights and Nights, based upon their proximity to Pearlstone or Ebonstone, respectively - Armored Skeletons and Skeleton Archers are a good examples of this for any who would want to test out this observation for themselves. Also, it seems that no souls of light or night are dropped on the surface. Cavern layer or deeper is recommended.