Wave is a +4 Halberd that can be crafted by Cromwell if the player can supply him with the Wave Shaft, the Wave Blade, and 7500 gold pieces. It is one of the few +4 weapons that can be found in Baldur's Gate II, and has the unique ability to instantly slay Efreeti, Fire Elementals and Salamanders.
Wave is based upon a magical halberd from the adventure "White Plume Mountain", alongside Blackrazor and Whelm, of which only Blackrazor receives a conversion attempt in the game.
In-game description Edit
Forged in antiquity by a cult devoted to the goddess Umberlee, this weapon of vengeance was designed to aid the cult's champion in retrieving a holy artifact from the fire giants of the Storm Horn Mountains. That was a lot of hope to place in one champion, and unfortunately the Wave had been lost ever since.