Possible Clues:

• Oswald Cobblepot's nom de crime
• Bird of the Antarctic
• Antarctic seabird with flippers for wings
• With the paper, back in the water
• Aquarium favorite
• 27 across, and there you have it in black and white
• King or emperor, perhaps
• Publisher and writer putting arm round compiler
• Bound not to fly and bound not to be hard at the back
• Fleetwood Mac album like a Batman foe?