a zanpakuto is a sword that reflects the second half of you and forms that into a weapon. 

LEVEL 5: when not summoned it is a standard katana like sword, but has the ability to awaken and take the form of another weapon (the first weapon it picks is its permanent awakened form) this  increases your strength by 3 (and 2 d4 damage per level) but can only be used 6 times per day. awakening your zanpakuto last 3 turns.

LEVEL 10: you can also use bankai that will change your zanpakuto again into a new form, this temporarily increases your dex by 3 and your STR by 5, this ability can be used once per day (long rest) and last 4 turns.

 

FOR AWAKENED ZANPAKUTO: roll a d6 and that is your zanpakuto's awakened form.

1- long sword (add 2 damage die)

2- tridant (add 2 damage die)

3- scimitar (add 2 damage die) 

4- spear (non-throwable) (add 2 damage die)

5- great axe (add 4 damage die)

6- katana (use short-sword stats, add 5 damage die)

 

FOR BANKAI: roll a d4

1- tri-blade sickle (use sickle stats x3)

2- rapier (add 6 damage die)

3- Glaive (add 6 damage die)

4- scimitar (add 7 damage die)

 

 

 

Proficiency with a Longsword allows you to add your proficiency bonus to the attack roll for any attack you make with it.

Notes: Damage: Melee Weapon Attacks, Versatile, Sap