Chalsembyr's Heart was a finely crafted greatsword forged of cold iron and gold, with a lion motif. The cross guards were shaped like lion's paws, and where they met the blade at the rain guard was an image of a lion's head, in profile on one side, face-on on the other. The hilt was bound in white leather and gold wire. Set into the pommel was a large, brilliant-cut white diamond, circled by five rectangular fiery yellow corundums. The cold iron blade was tinted with gold, with the words "Seek the High Seat Always" written in the Celestial language etched on both sides.
According to legend, Bertold the Seeker was a paladin of Torm who embarked on the traditional quest to rediscover the lost kingdom of Chalsembyr, the realm of the once-mortal Torm. To aid him in this endeavor, clerics of the House of the Hand temple in Procampur, the Vast, forged Chalsembyr's Heart. Bertold carried the sword with him on his journeys.
Finally, while crossing the Toadsquat Mountains of the southeastern Shaar, Bertold was ambushed by ogres and slain. He was unaware of his sword's soul binding power, however, and rather than go to the House of the Triad, Bertold's soul went into Chalsembyr's Heart.
There it would remain until another found and claimed the sword, to become the beneficiary of Bertold's knowledge and experience. However, the sword was lost after Bertold's death and not found by 1374 DR. Many paladins of Torm sought it around Faerûn.
The legend told that if another paladin wielded Chalsembyr's Heart and died, then their soul would also go into the sword, freeing Bertold to finally ascend to the afterlife. Thus each paladin would serve as a guide to the next one to seek Chalsembyr.
Chalsembyr's Heart functioned similarly to a holy avenger: though normally a +2 cold iron greatsword, it became a +5 holy cold iron greatsword in the hands of a paladin. However, it lacked the holy avenger's other powers.
The sword was also intelligent, bearing the bound souls of its deceased wielders. Inhabited by Bertold the Seeker, this was a lawful good, wise and charismatic soul, with the ability to see, listen, and read normally and able to communicate telepathically. It was knowledgeable in history with regards to Chalsembyr and in deciphering ancient and obscured writings. The sword's goal was to locate the lost kingdom of Chalsembyr.
The sword could be used to cast detect thoughts at will.
If wielded by a paladin of Torm who died, then Chalsembyr's Heart could absorb that person's soul and bind it within the sword, similar in effect to the spell soul bind, albeit with benevolent purpose. The purpose of this was to preserve the knowledge and findings of those who sought Chalsembyr, so that they might be passed on to future seekers.