Don't forget the elemental spirit guardians. Even Aku didn't have time for that and he's immortal. Magical jewels have always been more trouble than they're worth, in his own opinion. Aku slumps, almost resigned to the continuous burning of his shackles. He's just so tired. Too tired to be cranky over her jab at his own stupidity. He merely rumbles unhappily in the back of his throat.

As for the contract: "I do not know its whereabouts but I do know that it is infused with my essence and must be destroyed." Who knew giving away such an infinitesimal part of himself could lead to all this?