Here is the full list of all 99 Fighter Within achievements worth 1,000 gamerscore.
You have performed 100 Ki Long Range Swaps
You have performed 100 Ki Long Range Attacks
You are now a white and red 9th dan belt
You have performed 100 Ki Short Range Swaps
You are now a white and red 8th dan belt
You have performed 100 Ki Long Range Slams
You won 20 matches in a row against a green belt opponent
You are now a white and red 7th dan belt
You are now a white and red 6th dan belt
You put your green belt opponent in Ring Out in less than 30 seconds
You won 10 matches in a row against an orange belt opponent
You are now a black belt 5th dan
You won by KO against an orange belt in less than 20 seconds
You have won 30 fights in local multiplayer mode
You are now a black belt 4th dan
You have used the first Ki Cell 300 times
You are now a black belt 3rd dan
You are now a black belt 2nd dan
You have completed Arcade mode with Yu Bei
You have completed Arcade mode with every character
You have performed 100 Ki Short Range Slams
You have performed 100 Counters
You are now a black belt
You put your yellow belt opponent in Ring Out with 10% left on your life bar
You have won 50 fights by Ring Out
You won a match with each fighter
You have completed Arcade mode with Chayan
You have completed Arcade mode with J-Gun
You performed 50 Finishing moves
You have completed Arcade mode with Loa
You performed 10 close combat attacks on pole (Combo / Counter / Auto Counter / Throw)
You have completed Arcade mode with Maze
You have won 50 fights by KO
You are now a brown belt
You have performed 50 Auto Counters
You won by KO against a yellow belt in less than 30 seconds
You won 3 matches in a row against a yellow belt opponent
You won a match in each arena
You have completed Arcade mode with Sabina
You have performed 50 Throws
You have completed Arcade mode with DJ Joao
You performed 10 special Ki attacks on pole (Back Move / Front Move / Swap / Slam)
You have completed Arcade mode with Vân
You have completed Arcade mode with Mia
You are now a blue belt
You have used a stick 10 times
You have won 50 fights in Solo mode
You have completed Arcade mode with Færgas
You have performed 100 Combos
You have completed Arcade mode with Vince
You have used a Pole 10 times
You performed 1 special Ki attack on pole (Back Move / Front Move / Swap / Slam)
You have won 10 fights by Ring Out
You performed 10 Finishing moves
You have completed the Arcade Mode with Matt
You have used a Pole
You have performed 10 Ki Long Range Attacks
You have won 20 fights in Solo mode
You have completed the fifth Chapter of Initiation mode
You have performed 10 Ki Long Range Slams
You have performed 10 Ki Long Range Swaps
You performed 1 close combat attack on pole (Combo / Counter / Auto Counter / Throw)
You have used a stick
You have performed 10 Ki Short Range Swaps
You have completed the fourth Chapter of Initiation mode
You have won 10 fights by KO
You are now a green belt
You have completed the third Chapter of Initiation mode
You have used the first Ki Cell 10 times
You have performed 10 Ki Short Range Slams
You have completed the second Chapter of Initiation mode
You are now an orange belt
You have completed the first Chapter of Initiation mode
You are now a yellow belt
You have performed 5 Throws
You have performed 5 Auto Counters
You have performed 10 Counters
You have performed a Counter
You have performed 10 Combos
Win 300 fights in local multiplayer mode
Win 300 fights in Solo mode by KO
Win 300 fights in Solo mode by Ring Out
Become a red belt 10th dan
Perform 1000 Combos
Perform 500 Auto Counters
Perform 500 Throws
Perform 1000 attacks with the first Ki Cell
Perform 500 Ki Short Range Swaps
Perform 500 Ki Short Range Slams
Perform 500 Ki Long Range Attacks
Perform 500 Ki Long Range Swaps
Perform 500 Ki Long Range Slams
Use a Pole 100 times
Use a stick 100 times
Ring Out a blue belt opponent in less than 20 seconds
Defeat a blue belt opponent performing only Counters
Win a match thanks to a slam against a black belt opponent
Ring out a black belt opponent with a stick
Defeat a red belt 10th dan opponent