.cns file
[mcode];Night Slash
[Statedef 3000]
type = S
movetype = I
physics = S
velset = 0,0
value = 0
ctrl = 1
anim = 3000
sprpriority = 2


[State 3000, Helper]
type = Helper
trigger1 = AnimTime(5) = 1
helpertype = normal ;player
name = "NightSlash"
ID = 3001
stateno = 3001
pos = 60,-200
postype = p1    ;p2,front,back,left,right
facing = 1
keyctrl = 0
ownpal = 0
supermovetime = 999999
pausemovetime = 999999

[State 3000, ChangeAnim]
type = ChangeAnim
trigger1 = !AnimTime = 0
value = 0
ctrl = 1
;ignorehitpause =
;persistent =

[StateDef 3001, Night Slash 2]
type = S
physics = N
movetype = I
velset = 0,0
ctrl = 0

[State 3001, HitDef]
type = HitDef
trigger1  = AnimElem = 3
trigger2  = AnimElem = 4
trigger3  = AnimElem = 5
trigger4  = AnimElem = 6
trigger5  = AnimElem = 7
trigger6  = AnimElem = 8
trigger7  = AnimElem = 12
trigger8  = AnimElem = 13
trigger9  = AnimElem = 14
trigger10 = AnimElem = 15
trigger11 = AnimElem = 16
trigger12 = AnimElem = 17
trigger13 = AnimElem = 18
attr = S, NA
animtype = Medium
damage = 10,5
guardflag = MA
pausetime = 8,12
sparkno = 0
sparkxy = 0,0
hitsound = 0,0
guardsound = 0,0
ground.type = High
ground.slidetime = 12
ground.hittime = 13
ground.velocity = -5.5
air.velocity = -2.5,-4
fall = 1
fall.recover = 0
air.fall = 1

[State 0, ChangeState]
type = ChangeState
trigger1 = anim = 3002 && animtime = 0
value = 3002
ctrl = 0

[StateDef 3002, Night Slash 3]
type = S
physics = S
movetype = I
velset = 0,0
ctrl = 0
anim = 3002
sprpriority = 1

[State 0, DestroySelf]
type = DestroySelf
trigger1 = !animtime[/mcode]
.cmd file (Attack Command)
[mcode][command]
name = "NightSlash"
command = ~c[/mcode]
.cmd file
[mcode][State -1, NightSlash]
type = ChangeState
value = 3000
triggerall = !numhelper(3001)
triggerall = command = "NightSlash"
triggerall = statetype != S
trigger1 = ctrl[/mcode]

Animation:

Helper