World War III: Friendly characters named Osiris modify their attack values by +1 if they are not on their starting click. Friendly characters named Isis modify their defense values by +1 if they are not on their starting click.

Hell is Here!: Black Adam can use Charge. He can use it normally, or he can be given a double power action to use Charge with a locked speed value of 10 if he doesn't use the Carry ability or Super Strength.

Lightning Regeneration: Black Adam can use Regeneration. If he uses it and heals, after actions resolve deal 1 penetrating damage to each opposing character within 2 squares.

Defender of Khandaq: Black Adam can use Impervious, but if he would be dealt 4 or more damage, he reduces that damage by 3 instead of 2. His powers and abilities can't be countered except for his Outwit.

Errata

The keyword on his card named "The Society" is instead "Society".

What is this double power action thing that Hell is Here! is talking about?
See the Double Power Actions entry for more information.

What happens if Black Adam is on a click with the Defender of Khandaq special power, but something prevents him from using Impervious? Say, for example, that DC75 Atrocitus hits him with Burn Through Defenses and turn the Impervious into Invulnerability... does Black Adam still reduce the damage by 3?
The change to damage reduction described in Defender of Khandaq is specific to Impervious; if Black Adam can't use Impervious for some reason, he does not get the special damage reduction. In the case of Burn Through Defenses, for example, he would use plain old Invulnerability to reduce any damage dealt by Atrocitus.

I've heard something about an errata to this guy to make him have the symbol... where can I find that information?
That information doesn't exist. This character does not have the symbol.