Toad Liu Hai

Liu Hai is an ancient spirit of chance and fortunate in DuckTales.

Background
Liu Hai is described as a "luck vampire", a demon that feeds off the luck of others, thereby absorbing their fortune and abusing it for his own benefit. Those who fall victim of his greed become prisoner in his false hotel/casino, House of the Lucky Fortune, which is nothing more than a trap created to lure in unsuspecting patrons and potential prisoners. Gladstone Gander, widely considered to be the luckiest duck in the world, is lured in by Liu Hai and falls under his ownership. To escape, Gladstone calls to his uncle Scrooge McDuck, and cousin Donald Duck.

Role in the series
Liu Hai first appears under the guise of House of the Lucky Fortune's manager. He tries to talk Scrooge McDuck into becoming a hotel guest, but McDuck gets the best of Liu Hai and makes a break for the exit, with his family in tow. Gladstone tries to stop Donald from leaving, but his ball and chain appear as he nears the exit, revealing to his family that he's a prisoner. Liu Hai then reveals his true form and proposes that Scrooge take Gladstone's place, as the richest duck in the world is more valuable than someone who just so happens to be lucky. Scrooge challenges Liu Hai to a game, to which the the latter accepts. Donald is chosen to represent the Duck family, while Gladstone is chosen to represent Liu Hai; whomever wins is set free, whomever loses must remain under Liu Hai's control. In a turn of events, Donald wins and becomes Liu Hai's new prisoner. However, Liu Hai becomes weak and frail after absorbing Donald's "luck", which happens to be truly abysmal. As a result, both Liu Hai and his hotel vanish into oblivion.