Midnight Crew

The Midnight Crew is a non-canon group of antagonists originally paid to appear through a donation by Mayonaka. First appearing in extra episode 13, they were summoned by Problem Sleuth to take on Demonhead Mobster Kingpin, but then changed their alliances to DMK's side due to a slight mishap with a some Hunk Rump cards. The crew members are all based on one the four suits in a deck of cards respectively, with the exception of Mobster Kingpin, who is not an original member of the crew.

Spades Slick
The leader of this mysterious gambling group. He wields the CAST IRON HORSE HITCHER. Almost nothing about him is known, except that he supposedly wields sinister shadow-based magic. One might conjecture that the rest of the Crew can do so as well, though we have yet to see if this is so.

While performing HIVE RAGTIME: FILL'EM WITH MIDNIGHT, Spades Slick can jazz up a piano hard enough for it to be ridden like a mechanical bull.

Hearts Boxcars
The tall, brawny-looking member of the group. He wields a TV ANTENNA. Not much is known about him; He thus far appears to be a laid-back guy, and is capable of procuring COLORFUL NIGERIAN ROBES at a moment's notice for them to use.

While performing HIVE RAGTIME: FILL'EM WITH MIDNIGHT, Hearts Boxcars can pluck the shit out of a double bass.

Diamonds Droog
The tall, intimidating looking fellow of the group. He wields the ULTRA-VIOLENCE CUESTICK. Little is known about him, though he appears to have a short temper, as illustrated by his lashing out at Hearts Boxcars when he brought a handful of COLORFUL NIGERIAN ROBES for them to wear. Such an attribute doesn't seem that surprising, considering that he does wield an ULTRA-VIOLENCE CUESTICK.

While performing HIVE RAGTIME: FILL'EM WITH MIDNIGHT, Diamonds Droog can blow a mean saxophone.

Clubs Deuce
A short and stout crew member. He wields the CROOK OF FELONY. Almost nothing has been told of him except that he might be quite similar to Ace Dick seeing as when he aggresses AD he bludgeons him in the snout to establish similarity. If this just has to do with looks or not is impossible to tell at the moment.

While performing HIVE RAGTIME: FILL'EM WITH MIDNIGHT, Clubs Deuce can turn out a devastating oboe performance.

Shadow Mobster Kingpin
Mobster Kingpin who has been enveloped in a shadow by Spades Slick, seeing as SS didn't think the original MK was "quite cutting it somehow" to join their group.

While performing HIVE RAGTIME: FILL'EM WITH MIDNIGHT, Shadow Mobster Kingpin can blow his trombone with intense feeling.

Trivia

 * The quickest way of dealing with the Midnight Crew would of course be to just let PS unsummon them. Nobody would ever think of doing that though.