Hars, Longbow of Flame

Continuing the story of the "Five Cousins":

When the Duchess' weaponsmiths set out to craft the "First Cousin", Argol, Crossbow of Frost, for an eccentric Gnomish tinkerer from the Kron Hills to the north, it was determined that an all metal construction would be detrimental to the magical effect desired.  The Duchess selected her missing son's favorite tree (he was an odd boy, who enjoyed the forest as much as the hill; possibly due to the greater abundance of things he could chop with his axe), and had it cut down to be used for the wood in Argol's construction.  The excess wood was used to create the "Second Cousin", Hars, Longbow of Flame.  All of the excess was needed, dwarven woodworking not being on par with their ancient metalcraft.

One enduring tale remains regarding Hars.  The elven hero present and the dwarven smiths bickered constantly during Hars' creation, so much so that the smiths begged the Duchess to slight their guest or deny him a weapon.  She weighed the cost of refusal, then acquiesced to them smiths' request in part: Hars was presented to the half-elven hero, and the elf was gifted the more sinister "Cousin", Sairu.

Click to enlarge

5E game info for Hars, Longbow of Flame:

• Required level for attunement 5th: While the bow will radiate "transmutation" magic when examined by Detect Magic, it will not function as a magical weapon unless wielded by an owner of 5th level or greater (attunement is not required for this feature). 
• Attuned @ 5th Level: The bow counts as a magical weapon. It also deals an additional +1d4 fire damage when it hits with a ranged attack. 
• Attuned @ 9th Level: The bow also grants the attuned the ability to cast "Aganazzar's Scorcher" as a 3rd level spell. You must finish a long rest before you can use this feature again. 
• Attuned @ 13th Level: The bow also grants the attuned resistance to fire damage. 
• Attuned @ 17th Level and Above: Unknown. Theories include possible sentience, possible increases to damage or damage absorption, and/or possible additional fire-themed abilities.