Guenhwyvar
Guenhwyvar was created by the ranger-wizard Anders Beltgarden. The onyx figurine, referred to in Dungeons and Dragons 3.5 Edition rules as a "Figurine of Wondrous Powers," was originally owned by Josidiah Starym of Myth Drannor, and has also been possessed by the drow mage Masoj of House Hun'ett, whom Drizzt Do'Urden killed in battle. Drizzt then took the figurine from the ground (where Masoj had left it) because he could not bear to see Guenhwyvar used to do evil; while observing Guenhwyvar forced to hunt down deep gnomes, Drizzt perceived emotional damage being done to a creature he admired and viewed as noble. In his time after leaving Menzoberranzan, Drizzt took to summoning Guenhwyvar as often as possible, to help combat the extreme loneliness that Drizzt faced. In this time they became even closer than before, and they share a deep empathy with each other. Guenhwyvar has saved Drizzt's life more than once in their common history. Even though some of Drizzt's companions (especially Wulfgar and Bruenor) were at first suspicious of the panther, it later became an important "team" member. During the Siege of Darkness, Guenhwyvar was nearly destroyed entirely because of the Time of Troubles, in which magic all across Faer�n was in complete chaos. Because of Catti-brie's quick thinking, Guenhwyvar was saved, and once the time of troubles passed things were restored to normal.
Guenhwyvar is very much like Drizzt. The panther accepts him as a master, but loves him as a friend. Guenhwyvar's relationship to Drizzt is unique. The panther can be summoned forth from the Astral plane up to 12 hours out of every 48 hours. Simply spending time on the Prime Material Plane slowly drains the panther's strength. It is possible for Guenhwyvar to stay longer than the limit, or to be summoned back sooner than usual, but it is extremely draining for the panther. If the panther is seriously injured or even if it suffers injuries that should be fatal while on the Prime Material Plane, the panther transports back to the Astral plane. Spending a sufficient amount of time there regenerates the cat completely and it can be called forth again. Guenhwvar also has the ability to take someone with her to a different plane of existence. This ability is first shown in The Crystal Shard, when Guenhwvar transported Regis the halfling to the Astral Plane, thus saving him from being crushed as the tower of Creshinibon was destroyed. Also, in Streams of Silver, the ability was viewed again when the Companions of the Hall were attacked by an insubstantial pegasus, which was able to inflict damage, but became insubstantial against any attacks directed towards it. In the fight, the panther took Drizzt to the plane that the pegasus really was at, allowing it to be effectively attacked.
Guenwhyvar is roughly 600 pounds (twice the weight of a normal panther), and is as smart as any person. Guenhwyvar is "ten feet long, at least, with muscled shoulders as high as a tall man's chest."
Guenhwyvar while attacking a demon named Herzgo, falls through the shadow gate and is trapped in Shadowfell held captive by Draygo Quick, and is no longer connected to the figurine. Drizzt is approached by a shifter and is offered back Guenhwyvar in exchange for Charon's Claw, an offer that Drizzt refuses.