Bósi has discovered mention of a mighty axe made of mithril in one of the records you found and seeks to learn whether it might still be found.
'These pages mention something curious indeed, ${PLAYER}: an axe made entirely of mithril, light enough to be wielded one-handed but strong enough to fell any foe or rend any armour with a single sweep! Zigilburk, it was called, and it appears to have been forged in Durin's time by one called Ongli. Hm. I have not heard that name before. How can it be that one so skilled would not be remembered in legend?
'There is more to be learned on these pages. Could it be that Zigilburk might yet be found?
'My son Bori has been wracked by grief ever since Bróin was slain before the Doors of Durin. Bring him these pages and tell him of Zigilburk. It will do him well to have other thoughts upon which to brood. Go up the stairs on the eastern side of the chamber and through the door into the Chamber of Command; my son Bori is there, and Brogur also.'
Bori is in a small room off the eastern side of the Chamber of the Cross-roads.
Bósi has given you back the dusty pages which hold clues to the location of Zigilburk, hoping that your delivery may raise his son's spirits.
Katûb-zahar, the Word-hoard of Durin, is somewhere on the eastern side of the Great Delving, north of a large statue of Durin.
Bori told you that if you can find the place called Katûb-zahar, he may be able to discover the location of the mysterious mithril axe, Zigilburk.
Bori is in the Chamber of Command; it is the room up the eastern stairs in the Chamber of the Cross-roads, at the southern end of Durin's Way. It can be reached from the Great Delving.
You have located a plaque that marks the location of Katûb-zahar and should return to Bori with the news.