My landsknecht miss frequently, what affects accuracy?

Sometimes, his attack misses. His miss is annoying, because he has the largest attack in my team. Why does he miss? What affects missing an attack? How can I increase his accuracy?

For comparison, here are the complete stats of my team (I have only 5 member in my guild):

Thomas (Landsknecht):
  LVL : 4
  HP  : 57
  TP  : 25
  STR : 15
  TEC : 6
  VIT : 8
  AGI : 7
  LUC : 6
  ATK : 36
  DEF : 23

Victor (Protector):
  LVL : 4
  HP  : 61
  TP  : 28
  STR : 7
  TEC : 7
  VIT : 11
  AGI : 5
  LUC : 7
  ATK : 27
  DEF : 28

Angeline (Medic):
  LVL : 4
  HP  : 43
  TP  : 49
  STR : 8
  TEC : 10
  VIT : 5
  AGI : 6
  LUC : 8
  ATK : 26
  DEF : 17

Marie (Troubador):
  LVL : 4
  HP  : 50
  TP  : 37
  STR : 5
  TEC : 9
  VIT : 5
  AGI : 8
  LUC : 9
  ATK : 25
  DEF : 15

Gerald (Gunner):
  LVL : 4
  HP  : 44
  TP  : 38
  STR : 9
  TEC : 8
  VIT : 6
  AGI : 5
  LUC : 9
  ATK : 30
  DEF : 16