Twisted Metal/WMG

Calypso's real name is William Sparks.
This is practically Fanon. His daughter's name is Krista Sparks, suggesting Sparks to be his surname. And in Twisted Metal: Small Brawl, the character is named Billy Calypso.

The Black Box in the first game involved Quatro.
The alien ship that shot down an airplane was a bounty Quatro was after. Commander Mason works at Area 51 (one of the levels in Twisted Metal III), which have connections to the Galactic Center.

The timeline
Despite certain games considered Canon Dis Continuity, here's how all the games can fit (with a few alterations):

~1900s: A circus-type caravan called "High Octane" travels across the country, spreading destruction everywhere.

~1971: During the Vietnam War, a soldier and his squadmate Benny were taken captive. The soldier was forced to eat the deceased Benny.

~1985: A young boy named Needles Kane finds himself amazed by the contest. He steals an ice cream truck and runs off in its pursuit.

~1993: A man named William Sparks, his wife, and daughter Krista died in a terrible car crash. ~William made a deal with Mr. Ash to come back to life in exchange for souls. ~He also obtained powers to offer wishes from Minion (as a result of a deal or by trickery). ~His newfound power and his resurrection manifested into a demon named Black, which inhabits his prized possession - a ring.

~1995: William re-emerged and changed his name to Calypso. ~He came across the traveling circus. He took over and renamed it the Twisted Metal tournament. He placed the Arena in Los Angeles. ~The 1st ever Twisted Metal competition takes place. ~Bruce Cochrane is searching for a way to make his South Central neighborhood safe.

~1996: The 2nd annual competition.

~1997: The 3rd annual competition.

~1998: The 4th annual competition.

~1999: The 5th annual competition.

~2000: The 6th annual competition. ~Needles Kane escapes from a mental ward and became a serial killer called Sweet Tooth. Among his victims was a man named Scott Campbell at a local circus, who became a wandering spirit. ~Three days later, Scott's wife gives birth to a little girl. ~Sweet Tooth is searching for his friend Crazy Harold the Wacky Lunch Sack.

~2001: The 7th annual competition.

~2002: The 8th annual competition.

~2003: The 9th annual competition.

~2004: The 10th annual competition. Minion is the winner.

~2005: The 11th annual Twisted Metal competition. The event where the first game takes place. ~Agent Amanda X was hired by the people of L.A. to take down Calypso. ~Sweet Tooth's split personality Marcus Kane steals the abandoned Roadkill, and plans to enter the next competition. ~Charlie Kane ends up as Calypso's slave and becomes Dark Tooth.

~2006: The 12th annual competition. Twisted Metal 2 takes place.

~2007: The "Great Earthquake of 2007".

~2008: Twisted Metal III takes place.

~???: Sweet Tooth leads a coup of midget clowns to overthrow Calypso and takes over the tournament. Twisted Metal 4 takes place. ~Calypso and Sweet Tooth fight over the ring, and end up releasing the souls and trapping them inside as they fight for control. ~A boy named Billy found the ring, and holds his own little "tournament". Twisted Metal: Small Brawl (more or less). ~Calypso and Sweet Tooth are eventually freed from the ring.

~???: Warhawk captures Sweet Tooth in the city of Midtown. He is sent to Blackfield Asylum nearby, which is where Calypso comes across and holds a new tournament. Twisted Metal: Black takes place.

~???: Twisted Metal: Head-On takes place.

The Saints will be guest characters in a future installment.
Come on, don't act like you can't see this happening. They're no stranger to driving cars, murdering innocent people, and leaving unspeakable amounts of destruction in their wake. Only dilemma is: what would they wish for?

Marcus Kane will come back as Minion.
He would make a Deal With the Devil to get revenge on Calypso for tricking him. Also, it would make for an interesting Mythology Gag from Black.

A central theme of a sequel to the 2012 installment will be a battle for Sweet Tooth's legacy, culminating in a battle between the Kane children.
The Sequel Hook in the ending is likely leading up to some confrontation.

The two boys that drowned Raven's friend are the TM Black version of Mike & Stu.
Two idiot kids who drowned a girl for no good reason, it seems to fit the profile.

Why you see the same opponents you just killed in the next match.
Calypso resurrects them and regenerates their car to keep the tournament going, and only after the victor has won all the matches do the other competitors stay dead.