This bow started out as an ordinary composite long bow?. It was made for a priest of Solonor Thelandira as a gift for his induction into the order. It was made by the long dead master bowyer Ardruin Theneas? and was treated as a treasure by its first owner.
Well treated, the bow would ordinarily have lasted one or two hundred years. But the priest lavished such care on it that it has now lasted for generations in the elven family.
The blessing Darnus laid upon the bow seemed to keep it in good condition, and coupled with the care it received by Arden, the second owner, it was still usable after another hundred fifty years. Around this time Arden's daughter Saryn? took the vows of Solonor and the bow was blessed again in Solonor's name and passed on to her.
Saryn treated the bow much like her father and grandfather, keeping it in perfect condition for another fifty years. At this point in the bow's life a war sprang up between the elves and an army of orcs who attempted to invade the elven woods. The bow was given a blessing by the high priest of the church and given the name Cleathalas. Cleathalas enabled Saryn, already a great archer to make nearly impossible shots in the defense of her homeland.
At the end of the war Ardruin and Darnus made the trip to the other side, but before they let go of their lives on the Prime they decided to honor Saryn and Cleathalas for the work they did in the war. The two elves spent several days enchanting the bow and presented it to Saryn when they were done. They then left this world for the next.
Cleathalas has been viewed as a holy item of the church ever since then, but has been kept in the same family, passing from one generation of priest to another, always on the day of their induction. After a time the bow was given to Finglas. Upon his return to the physical world he took up Cleathalas again.
In game terms, Cleathalas is a composite long bow +3 with heartseeking. Whenever a natural 18, 19, or 20 is rolled on the attack, the target must make a save v. death or die, the arrow piercing the heart. If the save is successful the creature takes normal damage. Creatures without hearts are exempt from this power.