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First of all: no-one has the slightest idea. More than five thousand years have passed between the War of Wrath and the awakening of the balrog and so it's reasonable to think it was not part of everyday lore. Also, TA 1980 is the year when the Nazgûl return to Mordor and lay siege to Minas Ithil, so it's not unreasonable at the time to think Durin's Bane is another kind of Sauron's terrible servants. No-one but the dwarves saw it and most of those who saw it didn't survive to tell the tale. Also, the appearance of Durin's Bane — whatever it is — have rekindled the beyond-ancient animosity between the Elves and the Dwarves (ancient: it is rooted in the very creation of the dwarves and Ilúvatar adopting them) so if there were any survivors they certainly did not sit down with Galadriel or Elrond to give them a nice description of Durin's Bane.

So while there's a common knowledge about Durin's Bane as a being far stronger than a dwarf or even an army of dwarves, as for how it looks and even what it is, no-one has the slightest idea.

In the movie Saruman had a book showing the balrog as Durin's Bane, well, that just doesn't fit the narrative of the book.

Edit: that Legolas recognized the balrog as such is less surprising, we know his grandfather came from Doriath and saw the War of Wrath and surely have told tales of it many a times to his son and possibly his grandson although there's no data when Legolas was born — for all we know he might have been born in the First Age himself. While many thousand years have passed for the elves it's only three generations.

First of all: no one has the slightest idea. More than five thousand years have passed between the War of Wrath and the awakening of the balrog and so it's reasonable to think it was not part of everyday lore. Also, TA 1980 is the year when the Nazgûl return to Mordor and lay siege to Minas Ithil, so it's not unreasonable at the time to think Durin's Bane is another kind of Sauron's terrible servants. No one but the dwarves saw it and most of those who saw it didn't survive to tell the tale. Also, the appearance of Durin's Bane — whatever it is — have rekindled the beyond-ancient animosity between the Elves and the Dwarves (ancient: it is rooted in the very creation of the dwarves and Ilúvatar adopting them) so if there were any survivors they certainly did not sit down with Galadriel or Elrond to give them a nice description of Durin's Bane.

So while there's a common knowledge about Durin's Bane as a being far stronger than a dwarf or even an army of dwarves, as for how it looks and even what it is, no one has the slightest idea.

In the movie Saruman had a book showing the balrog as Durin's Bane, well, that just doesn't fit the narrative of the book.

Edit: that Legolas recognized the balrog as such is less surprising, we know his grandfather came from Doriath and saw the War of Wrath and surely have told tales of it many a times to his son and possibly his grandson although there's no data when Legolas was born — for all we know he might have been born in the First Age himself. While many thousand years have passed for the elves it's only three generations.

First of all: noone has the slightest idea. More than five thousand years have passed between the War of Wrath and the awakening of the balrog and so it's reasonable to think it was not part of everyday lore. Also, TA 1980 is the year when the Nazgûl return to Mordor and lay siege to Minas Ithil and so it's not unreasonable at the time to think Durin's Bane is another kind of Sauron's terrible servants. Noone but the dwarves saw it and most of those who saw it didn't survive to tell the tale. Also, the appearance of Durin's Bane -- whatever it is -- have rekindled the beyond ancient aminosity between the elves and the dwarves (ancient: it is rooted in the very creation of the dwarves and Illuvatar adopting them) so if there were any survivors they certainly did not sit down with Galadriel or Elrond to give them a nice description of Durin's Bane.

So while there's a common knowledge about Durin's Bane as a being far stronger than a dwarf or even an army of dwarves, as for how it looks and even what it is, noone has the slightest idea.

In the movie Saruman had a book showing the balrog as Durin's Bane, well, that just doesn't fit the narrative of the book.

Edit: that Legolas recognized the balrog as such is less surprising, we know his grandfather came from Doriath and saw the War of Wrath and surely have told tales of it many a times to his son and possibly his grandson although there's no data when Legolas was born -- for all we know he might have been born in the First Age himself. While many thousand years have passed for the elves it's only three generations.

First of all: no-one has the slightest idea. More than five thousand years have passed between the War of Wrath and the awakening of the balrog and so it's reasonable to think it was not part of everyday lore. Also, TA 1980 is the year when the Nazgûl return to Mordor and lay siege to Minas Ithil, so it's not unreasonable at the time to think Durin's Bane is another kind of Sauron's terrible servants. No-one but the dwarves saw it and most of those who saw it didn't survive to tell the tale. Also, the appearance of Durin's Bane — whatever it is — have rekindled the beyond-ancient animosity between the Elves and the Dwarves (ancient: it is rooted in the very creation of the dwarves and Ilúvatar adopting them) so if there were any survivors they certainly did not sit down with Galadriel or Elrond to give them a nice description of Durin's Bane.

So while there's a common knowledge about Durin's Bane as a being far stronger than a dwarf or even an army of dwarves, as for how it looks and even what it is, no-one has the slightest idea.

In the movie Saruman had a book showing the balrog as Durin's Bane, well, that just doesn't fit the narrative of the book.

Edit: that Legolas recognized the balrog as such is less surprising, we know his grandfather came from Doriath and saw the War of Wrath and surely have told tales of it many a times to his son and possibly his grandson although there's no data when Legolas was born — for all we know he might have been born in the First Age himself. While many thousand years have passed for the elves it's only three generations.

First of all: noone has the slightest idea. More than five thousand years have passed between the War of Wrath and the awakening of the balrog and so it's reasonable to think it was not part of everyday lore. Also, TA 1980 is the year when the Nazgûl return to Mordor and lay siege to Minas Ithil and so it's not unreasonable at the time to think Durin's Bane is another kind of Sauron's terrible servants. Noone but the dwarves saw it and most of those who saw it didn't survive to tell the tale. Also, the appearance of Durin's Bane -- whatever it is -- have rekindled the beyond ancient aminosity between the elves and the dwarves (ancient: it is rooted in the very creation of the dwarves and Illuvatar adopting them) so if there were any survivors they certainly did not sit down with Galadriel or Elrond to give them a nice description of Durin's Bane.

So while there's a common knowledge about Durin's Bane as a being far stronger than a dwarf or even an army of dwarves, as for how it looks and even what it is, noone has the slightest idea.

In the movie Saruman had a book showing the balrog as Durin's Bane, well, that just doesn't fit the narrative of the book.

First of all: noone has the slightest idea. More than five thousand years have passed between the War of Wrath and the awakening of the balrog and so it's reasonable to think it was not part of everyday lore. Also, TA 1980 is the year when the Nazgûl return to Mordor and lay siege to Minas Ithil and so it's not unreasonable at the time to think Durin's Bane is another kind of Sauron's terrible servants. Noone but the dwarves saw it and most of those who saw it didn't survive to tell the tale. Also, the appearance of Durin's Bane -- whatever it is -- have rekindled the beyond ancient aminosity between the elves and the dwarves (ancient: it is rooted in the very creation of the dwarves and Illuvatar adopting them) so if there were any survivors they certainly did not sit down with Galadriel or Elrond to give them a nice description of Durin's Bane.

So while there's a common knowledge about Durin's Bane as a being far stronger than a dwarf or even an army of dwarves, as for how it looks and even what it is, noone has the slightest idea.

In the movie Saruman had a book showing the balrog as Durin's Bane, well, that just doesn't fit the narrative of the book.

Edit: that Legolas recognized the balrog as such is less surprising, we know his grandfather came from Doriath and saw the War of Wrath and surely have told tales of it many a times to his son and possibly his grandson although there's no data when Legolas was born -- for all we know he might have been born in the First Age himself. While many thousand years have passed for the elves it's only three generations.