Gold

Gold is a Cyborg Black Bird. See his account here. The backwards version of him is Dlog and the alternate version of him is Alternate Gold.

History
After another attempt to steal the eggs, the pigs are defeated again after a long and hard battle many birds died in. After a smart Foreman Pig finds a dead Black Bird, he ends up turning it into a cyborg named Gold that serves the pigs. Not too soon after, Gold introduces himself to the birds as a threat not to be taken lightly, and has an army of pigs attack the birds. During the attack, Gold ends up taking the eggs and then flies to the Pig Fortress. The birds then ends up finding out that Gold stole the eggs, so the birds start the final battle with Gold. The birds succeed in getting back the eggs, but are soon thrown into a cage getting lowered into a hot pot of lava. Gold asks for any last words, and a Black Bird launches himself into the fortress. He blows up right in front of Gold, which the explosion somehow gives him his memory back. He ends up stopping the cage from going into the lava, and the Foreman Pig who turned him into a cyborg comes to watch the birds die, so Gold throws him into the hot pot of lava, killing him. Gold then lowers the cage over to the platform next to the lava pot, and the birds thank him. King Pig also comes over to see what is happening, and Gold ends up throwing him into the lava also, killing him too. Soon after, the birds have a celebration because of the death of King Pig. But soon after, King Pig's son becomes the King Pig, which gives the birds the pig threat once more. Gold then promises to serve the birds forever, and never stop doing so. But during another attack on the birds with the new King Pig, the new King Pig ends up taking Gold to reprogram him, so he has no memory left. The birds quickly beat the small army of pigs, so the birds go to help Gold. The new King Pig turns Gold over to find the control panel, which he finds. Soon after the birds break into the fortress, and launch themselves at the King Pig. He falls, and the birds quickly get Gold out of the chains which held him while King Pig was reprogramming him, and Gold leads the birds to the control center of the fortress, which the birds blow up with TNT, and the birds quickly get out of the fortress to watch the fortress blow up. Gold then returns to the egg nest, getting ready for more pig attacks, which he suspects will come not to soon from the destruction of the Pig Fortress. Sometime after these events, Gold ends up battling an alternate version of himself in Angry Birds: Gold's Battle.