NetHack 3.4.3 – This patch adds a new role to the game: the Bard.
Download: Patch (30 KB)
Pre-compiled Windows binary (1.2 MB)
Spoilers
***WARNING***
PLEASE NOTE that this is still a beta patch, so there are many things that still don’t work.
Documentation:

To apply this patch, enter the nethack sources directory and type:
patch -p0 < bard-nh343.patch
I stole some minor portions of Nicholas Webb’s Biodiversity patch, namely the timeout for peacefulness in monsters (so pacifying monsters through songs only works for a while).

Stuff added

Objects

• Syrinx (reed flute) – Has the same effects of an harp, but is better for playing peaceful songs.

Monsters

• Charon (@): Not really an addition; it was already in the sources, just commented out. Guards the entrance to the Underworld (Hades).
• Cerberus (d): Same as above.
• Hades (L): Quest nemesis. Beware of him.
• Orpheus (@): Quest leader.
• Bard/Rhymer (@): Common player monster/quest guardians.

Also, some existing monsters were defined as deaf, so no songs affect them.

Artifacts

the Lyre of Harmony (magic harp)

• Carried: Magic resistance
• Applied: Bonuses for playing peaceful songs, penalties for the others
• Invoked: ? (not defined yet)

Behaviour changed

This patch adds a new skill: music playing. This enables the player to use normal musical instruments to cause special effects, depending on the skill level.
The following roles/races have this skill:

• Bard (expert)
• Monk (basic)
• Priest (basic)
• Elf (basic)

For all other races/roles, the behaviour of the instruments is *exactly* the same as before the patch (I hope so; please tell me if you find any bugs).
These songs use MP, as spells do. And like spells, there is a chance of success of playing a song, calculated upon dexterity and music skill, and charisma for peaceful songs. The idea of using MP for playing songs is debatable, but it is this way for primarily two reasons:

1. Introducing a limit for playing songs, to avoid situations where the player can just play a pacifying song every 5 turns or so to keep monsters around him peaceful. An (almost) invincible pacifist.
2. Songs have effects like spells have, that is, they’re magic. A different kind of magic, but one can’t expect to influence monsters that far only because a bard can play wonderfully; some magic must be involved, and thus MP.

Note also that one cannot play any magic songs while confused, stunned, or wielding a shield. (not done yet)