The songs that follow are powerful. If In Nomine were a more balanced system, I would probably want to conduct play testing before proposing them. Instead these can be though of as draft ideas, please feel free to modify them as you see fit.
Elemental Numinous Corpus don’t just change one aspect of the body, they transform the entire body, bringing multiple advantages and disadvantages. Liber Canticorum includes two versions of this type of song; Numinous Corpus (Flame) and Numinous Corpus (Stone). Both were Secret Songs.
With this in mind, I have decided that all Elemental Numinous Corpus will be Secret or Forgotten, depending on which Superior(s) know it.
As an additional restriction, I would only allow a character to use one such song at a time. In theory the restrictions on availability should take care of that, but PCs can always find a way.
This is a Secret Song known to Beleth and Vapula.
It causes the performer to become a creature of gears, cams, and hydraulics. The performer’s unarmed attacks gain +2 Power (which jumps to +4 at level 5), and incoming attacks rolls are penalized by by the song’s level. However, while in effect, none of the performer’s skill TNs (including attack TNs) can exceed their Precision + their level in this Song.
This is a Forgotten Song known to by Beelzebub and Makatiel.
This song causes the performer’s body to shift into an ambulatory pile of fecal matter. Anyone who makes physical contact with the performer must succeed on a Strength roll or be infected with a fecal-oral path disease like cholera, dysentery, or tapeworms. The Strength and Speed of the disease each start at 2, but the performer may increase one of the two (their choice at the time of singing) for each level.
If you really want this song in your game, Kobal might know it as a Secret Song.
Forgotten Song possibly known by some obscure ethereals.
As Numinous Corpus: Stone.
This is a Secret Song known to Marc and Mammon.
This mostly ornamental song will transform the performer’s skin into a treasure of silver, gold, platinum, and gemstones. This duplicates the effects of all three songs of Opening when dealing with someone who is Greedy (or who is appropriately obsessed or covetous).
This is a Secret Song known to Jean.
This song can be treated as a variation of Flame.
This song could allow a celestial to use the Ofanite of Lightining attunement.
This is a Secret Song known the only to Alaemon and Beleth.
This song transforms the performer into the stuff of shadows, granting them a TN bonus equal to the song’s level on both Dodge and Move Silently rolls and allowing them to pass freely through any barrier that is not well lit on either side. While in effect the performer will also have Vulnerability: Light at an equal level.
This is a Secret Song known only to Janus and Vapula.
This song transforms the performer into a cloud of steam, granting them a TN bonus equal to the song’s level on both Dodge and Move Silently rolls and allowing them to pass freely through any barrier that is not airtight. While in effect the performer will also have Vulnerability: Breeze at an equal level.
Forgotten Song known by Oannes and Vephar.
This can be treated as a variation of Plates, but the performer does not need to breathe and can increase their Swimming TNs by ½ the level (round up). The performer cannot simultaneously benefit from this and Numinous Corpus Spikes. Once the performer stops using this song, they cannot resume: it must be sung again.