One of the most disastrous days in the history of herodom, the day that became known as Darke Day was the day which Dr. Darke opened an interdimensional portal to Hell in order to conquer it and defeat his archenemy Dhrell. It is unknown at present why Dr. Darke undertook such a dangerous mission alone against such a powerful foe.
The battle did not go as planned. Dr. Darke was engaged by the legions of hell and while preoccupied Dhrell reinforced and used the portal to launch an invasion of Earth. Dhrell and his demonic horde caused substantial damage in Queen City, including destroying the Knights Tower, before being driven back into Hell by the Knights.
In the ensuing battle inside Hell, the Knights divided themselves -- half remaining behind to hold the legions at bay, while the other half withdrew to defend Earth. Dr. Darke sacrificed himself to seal the portal between the two realms and trap Dhrell in Hell once more.
Only four of the ten Knights remained on Earth following Darke Day. The press has taken to calling the year since the invasion of hell and the disastrous loss of half the Knights the start of a new Darke Age.