Suddenly, ninjas!

This ninja is disguised as:

1. Farmer
2. Travelling musician
3. Priest
4. Juggler
5. Herb seller
6. Itinerant scholar

And armed with:

1. Tanto (knife)
2. Ninjato (short sword)
3. Tonfa (sword catcher)
4. Bo (staff)
5. Naginata (Pole-arm)
6. Shuko-te (claws)
7. Kusari-gama (chain-scythe)
8. Fukiya (blowpipe)
9. Nunchaku
10. Johyo (Rope-dart)
11. Meteor hammer (chain-mace)
12. Bow

But also conceals (x2):

1. Shuriken (throwing stars)
2. Metsubishi (smoke bombs/pepper spray)
3. Kakute (poisoned ring-blade)
4. Tetsubishi (caltrops)
5. Kanzashi (sharpened hairpin)
6. Kunai (darts)

And has the power to:

1. Be invisible at night.
2. Distract with ventriloquism.
3. Travel unseen in a cat's shadow.
4. Walk over water.
5. Heal wounds with secret herbs.
6. Pass without leaving a trace.

As well as:

1. A supernatural ally.
2. A prized ancestral weapon.
3. The patrol schedule for the closest stronghold's guards.
4. A lover who will take revenge for their death.
5. A flute stolen from a demon.
6. A letter of introduction to a wealthy merchant.

This ninja is attacking because:

1. The clan swore an oath of eternal revenge against a character's ancestor.
2. The clan's demon patron has decreed the character's death without explanation.
3. The ninja intends to take the character's place to infiltrate a location or organisation.
4. The clan elders have divined an evil fate for the character.
5. The clan is allied with the character's political rivals.
6. The character has trespassed in an area sacred to the clan.

The ninja has also:

1. Poisoned the character's/party's food.
2. Rigged a trap in a place the character is sure to set foot.
3. Sent a message to local authorities denouncing the character as a criminal/traitor.
4. Concealed a poisonous serpent/spider in the character's belongings.
5. Hired a gang of thugs/killers.
6. Sabotaged the party's transport.

In dying the ninja:

1. Strikes an effective final blow.
2. Sets off an explosive.
3. Curses an opponent.
4. Dissolves into mist.
5. Summons ghosts.
6. Escapes, having fooled the character into killing a bystander.

The law of conservation of Ninjitsu: a ninja takes -1 to attack rolls and AC for each allied ninja present.