Here is the full list of all 48 Martial Arts Brutality achievements.
Win 10 Victories
Become a 1st Dan Black Belt
Earn a Brown Belt
Earn a Purple Belt
Earn a Blue Belt
Win 5 Victories
Win 4 Victories
Earn a Green Belt
Inflict a Massive Head Trauma KO!
Win 3 Victories
Earn a Red Belt
Win 2 Victories
Earn a Orange Belt
Earn a Yellow Belt
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Become a 5th Dan Black Belt
Become a 10th Dan Black Belt
Become a 15th Dan Black Belt
Become a 20th Dan Black Belt
Become a 30th Dan Black Belt
Become a 40th Dan Black Belt
Become a 50th Dan Black Belt
Inflict a Massive Internal Bleeding KO!
Inflict a Catastrophic Arm Trauma KO!
Inflict a Bleed Out KO!
Inflict a Blinded KO!
Inflict a Cardiac Arrest KO!
Inflict a Coma KO!
Inflict a Catastrophic Joint Trauma KO!
Inflict a Catastrophic Leg Trauma KO!
Inflict a Shattered Spine KO!
Inflict a Suffocation KO!
Become a Grand Master
Become an Eagle Grand Master
Become a Crane Grand Master
Become a Tiger Grand Master
Become a Viper Grand Master
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Become a Panther Grand Master
Become a Lion Grand Master
Become a Mantis Grand Master
Become a Wolf Grand Master
Become a Dragon Grand Master
Win 15 Victories
Win 20 Victories
Win 50 Victories
Win 75 Victories
Win 100 Victories