I justify it
with mythology
But whatever he sang, the rich clear words and the silvery notes from his harp were so enchanting that they always had a magical effect on everything around him. His songs could charm even rocks and rivers as well as humans and animals. Once when Orpheus was playing his splendid music in the forest, the oak trees pulled up their roots. They followed him down the mountainside and planted themselves by the seashore where Orpheus ended his song.
When the great adventurer Jason was about to set out on his search for the Golden fleece, Orpheus was invited to go along. Orpheus proved to be of great help on the long journey. When the tempers of the heroes of the ship flared up, Orpheus would sing a peaceful song and calm those who had been arguing. Sometimes when the rowing was long and tedious, Orpheus would begin to stroke his lyre. Then time would seem to float by and the rowers would not feel tired and they listened to the soft rippling music.
The time came when Jason and the Argonauts had to sail past the dangerous isle of the Sirens. The Sirens were beautiful creature who were part human, part bird. Their songs were so wonderful that any person who heard them would become enchanted. All the sailors who heard the Sirens' songs would hurl themselves overboard and swim to the island of the Sirens'. Lured by these strange maidens the men would die upon the jagged rocks around the isle. But as the argonauts came close to the rocky island of the Sirens, Orpheus began a splendid song of his own. Jason and this crew did not listen to the Sirens and were able to sail past the island unharmed.
After the Argonauts returned to Greece, Orpheus fell in love with a beautiful woman names Eurydice> They were married and a great feast was held in their honor. On the day of their wedding, Eurydice strolled through a nearby field and talked joyfully with her friends. But as she walked through the bright green meadow, she stumbled upon a poisonous snake. The huge serpent bit her and she died.
Orpheus was heartbroken over this cruel fate. He had been married and widowed on the same day. After many weeks of mourning, he decided that he would go to Hades,the land of the dead. There he would plead for his wife.
He came to the gates that lead to the underworld, playing on his harp. No living mortals were allowed to cross into the shadowy regions of the underworld. But Orpheus' sweet dad music moved the ferry and of the dead and he gave Orpheus a ride across the dark murky river Styx. Thus Orpheus entered the purple-darkened realm of the dead. Formless ghosts and spirits gathered around him. But Orpheus was unfrightened and continued to play his slow music about his lost wife. The Spirits began to weep and the huge vultures of the underworld listened to his song.The three-headed dog that guarded the Underworld stopped growling and laid down and whimpered at the dad tine. Orpheus passed by the coal-black stallions that pulled the chariot of Pluto. The horses' ears stood straight up when they heard the enchanting song. Finally the musician came before Pluto, King of the Underworld called Hades.All the jewels and precious metals that lie in the ground rightfully belonged to Pluto's domain. Thus he and his wife< Persephone, sat on the most magnificent thrones imaginable.Beside Pluto lay a magic helmet that would make anyone who wore it invisible. Here, before the King and Queen of Hades, Orpheus sang his sad, sweet song and pleaded to have his bride back. Even the rulers of the underworld were moved by h is music. Eurydice was called forth and she came still limping from the wound where the serpent had bitten her. The gods of Hades agreed that Orpheus could have his wife back, but only on the condition that he did not look back until he had reached the land of the living.
There's also the Pied Piper, who had to have more than just good flute skills in order to charm both rats, children, and then
disappear with the latter. And, if a nymph can be so beautiful it strikes a man blind, I can accept something so joyous or sorrowful that it kills.
As far as the deadly song, I justify it with metaphysics. First, in the novel
Dead Beat, necromancers animate the dead and keep them under their sway by using a drum beat. This drum beat symbolizes the undead's own heartbeat, tricking it into believing it's alive, and thereby interpreting the Necromancer's commands as its own. Extrapolating this to the Bard, the Bard could easily trick a living heart to follow, syncing up with the rhythm the bard sets out. And then the bard
stops, causing the heart to stop. A more simple explanation, the song of the Bard causes the individual to
will themselves to death.
Finally I justify it with a handwave:
it's magic. The bard has always casted spells (and I presume they still do in PF). If it helps you think about it, bards are just
very specialized wizard; music as both the verbal and somatic component, and it manifests only in terms of sound, charm and illusion. They exchange the Depth of their magic for their social skills. But they are still spellcasters. If a wizard can point at someone and turn them to stone, or just make them die (power word: Kill, finger of death, etc), then a Bard using music (since that's their form of magic) to do the same isn't beyond reason. Because
it's magic.
In all honesty, my biggest issue with the bard is that they get no respect. 4e's bard is
badass, and yet at the table I get sneered at for being a bard. I routinely get jokes about playing my lute in battle and so on. Even when I go out of my way to describe the fact I'm not a singy/music instrument bard, players
still make the assumption.
