From Rebirth of the Night Wiki

Spirits are entities that inhabit certain undead creatures or exist on their own. In the case of undead creatures, spirits appear as floating red orbs after "killing" the creature, and having an empty bottle in your inventory will capture them creating bottled spirits. Spirits are fundamental for their use in the ancestral infuser, but they also serve other purposes. All of those uses involve them being bottled.

Spirit mobs[edit]

Spirits that live for 200 ticks
Mob Amount of spirits
minecraft:wither_skeleton 1
minecraft:skeleton 1
mod_lavacow:banshee 1
betterslimes:spectral_slime 1
mod_lavacow:mimic 4
primitivemobs:skeleton_warrior 1
twilightforest:skeleton_druid 1
mod_lavacow:skeletonking 1
mod_lavacow:scarecrow 1
trumpetskeleton:trumpet_skeleton 1
specialmobs:specialskeleton 1
specialmobs:bruteskeleton 1
specialmobs:fireskeleton 1
specialmobs:gatlingskeleton 1
specialmobs:giantskeleton 1
specialmobs:knightskeleton 1
specialmobs:ninjaskeleton 1
specialmobs:poisonskeleton 1
specialmobs:sniperskeleton 1
specialmobs:spitfireskeleton 1
specialmobs:strayskeleton 1
specialmobs:specialwitherskelet 1
specialmobs:brutewitherskeleton 1
specialmobs:gatlingwitherskeleton 1
specialmobs:giantwitherskeleton 1
specialmobs:knightwitherskeleton 1
specialmobs:ninjawitherskeleton 1
specialmobs:sniperwitherskeleton 1
specialmobs:spitfirewitherskeleton 1
Spirits that live for 10600 ticks
Mob Amount of spirits
quark:wraith 1
twilightforest:wraith 1
mod_lavacow:banshee 1
mod_lavacow:avaton 1

Research Notes[edit]

"I remember stories about skeletons; they aren't like zombies no, more like wraiths and specters. You see, some are more attached to this world than others, so even when they die, their souls keep roaming around. Some of them will seek vessels to hop into and make a new home, a new body!"