Data accurate up to 2004
Marvin
Rank: 950
Weight Class: 340lbs
Competed:
October 2003 - March 2005
Marvinator
Rank: 1036
Weight Class: 120lbs
Competed:
April 2005
Mash-N-Go
Rank: 999
Weight Class: 175lbs
Competed:
August 1997
Massacre
Rank: 988
Weight Class: 210lbs
Competed:
May 2001
3.0
Mastakilla
Rank: 988
Weight Class: 220lbs
Competed:
May 2002
Mastiff
Rank: 997
Weight Class: 100kg
Competed:
June 2001
extreme 1
Matts Bammer
Rank: 1028
Weight Class: 60lbs
Awards: 1
Competed:
May 2001 - June 2005
Mauler
Rank: 958
Weight Class: 220lbs
Awards: 3
Competed:
August 1994 - August 2003
Max Damage
Rank: 975
Weight Class: 175lbs
Competed:
October 1999 - August 2000
3rd wars
Max Wedge
Rank: 1273
Weight Class: 120lbs
Awards: 6
Competed:
May 2002 - March 2005
MaxiMill
Rank: 978
Weight Class: 100kg
Competed:
June - August 2001
drw 1
Maximum Paralysis
Rank: 1019
Weight Class: 220lbs
Competed:
November 2001 - January 2003
Maximum Torque
Rank: 975
Weight Class: 100kg
Competed:
August 2001
drw1
Maximus
Rank: 1028
Weight Class: 340lbs
Awards: 4
Competed:
May 2001 - April 2004
Maximus
Rank: 987
Weight Class: 100kg
Competed:
June - October 2002
Maximus
Rank: 1031
Weight Class: 375lbs
Competed:
January - October 2002
Mayhem
Rank: 993
Weight Class: 100kg
Competed:
August 2003 - May 2004
Mazakari
Rank: 994
Weight Class: 175lbs
Competed:
August - September 2000
4th wars
Mean Green Fight'n Machine
Rank: 982
Weight Class: 60lbs
Competed:
March 2004 - November 2005
Mean green fighting machine with the drum removed to fight as a lightweight
Mean Streak
Rank: 1004
Weight Class: 100kg
Competed:
August 2003
Mecha Bubo
Rank: 986
Weight Class: 120lbs
Competed:
July 2003
Mecha-Chu
Rank: 978
Weight Class: 60lbs
Competed:
April 2003 - August 2004
WCR Inaugural
MechaVore
Rank: 1047
Weight Class: 220lbs
Competed:
May 2001 - May 2002
4/5.0
Mechadon
Rank: 1012
Weight Class: 325lbs
Awards: 5
Competed:
August 1999 - June 2000
Mechadroid
Rank: 988
Weight Class: 100kg
Competed:
January 2002
Mechaniac
Rank: 983
Weight Class: 100kg
Competed:
August 2003
Folkestone 2004
Mechanical Advantage
Rank: 1000
Weight Class: 120lbs
Competed:
April 2003
Editor's Note:
I'm Reasonably sure from pictures (http://web.archive.org/web/20190808183859/http://www.angelfire.com/electronic2/cerberus/dmonic3gallery/dmonic3gallery.html) that mechanical advantage is the 2nd unidentifed robot that defenestrator fights, however they could be 2 seperate robots
Medulla Oblongata
Rank: 912
Weight Class: 60lbs
Competed:
August 2003 - July 2005
Robotic Revolution 2005
Medusa 2000
Rank: 995
Weight Class: 175lbs
Competed:
August - September 2000
4th wars
Mega Hurts
Rank: 988
Weight Class: 100kg
Competed:
July 1998 - August 2003
Mega-Hurts
Rank: 997
Weight Class: 100kg
Competed:
September 2001
xt1
Megabyte
Rank: 1193
Weight Class: 220lbs
Awards: 12
Competed:
May 2002 - November 2005
Meltdown
Rank: 988
Weight Class: 115lbs
Competed:
May 2001
3.0
Melvin
Rank: 1009
Weight Class: 11.3kg
Competed:
August 1996
Menace
Rank: 1000
Weight Class: 340lbs
Competed:
May 2002
Merbot
Rank: 1012
Weight Class: 120lbs
Awards: 1
Competed:
October 2002
Mercenary
Rank: 977
Weight Class: 120lbs
Competed:
April 2005
Merlin
Rank: 1046
Weight Class: 100kg
Awards: 1
Competed:
August 2003 - November 2005
Winter Tour 2004, Modified with a wider flipper. Picture from Preston 05
Merrimac
Rank: 987
Weight Class: 165lbs
Competed:
August 1995 - August 1996
1996
Meshuggah
Rank: 977
Weight Class: 100kg
Competed:
August 2001 - July 2002
Dutch Series 2
Mean Green Fight'n Machine 
Merlin 
