Nice, I haven't seen any katanas yet. I went back on the main quest line. Here be dragons.
katanas and samurai armor is more of "the blades"style. u can get katanas from blades members, and you get the samurai armor from their temple.
So far i believe their are 2 unique katanas.
DRAGONBANE: a katana that can be found during the main dragon questline.it gains a 10pt damage boost against dragons, and otherwise has a shock damage. You can acheive it by ether.
1. grabbing it as soon as you enter the blades temple. it will be in a room on a table to the left of the entrance. what i did.
2. completeing the optional blades mission of slaying paarthemix.
3. stealing it, if you didnt grab it before.
If you grab it as soon as you enter the temple, its your to own. if not, you have to ether steal it, or slay the greybeards dragon leader, paarthemix. in order to get it legit.
EBONY BLADE: The ebony blade returns once more in a TES game. some may reconize its name and effects from oblivion, or morrorwind. it is a deadric artifact, which this time around takes the form of a giant two-handed katana.
It has a health draining bonus, And also grows stronger from "Deceit". meaning if you slay followers/anyone who trusts you, it strengths the blade.
It can be attained by:
In whiterun, listen around for rumors by asking the woman at the bannered mare. She will mention something about the jarls son being distant. after this, talk to the jarl himself. This will open the questline to retrieve the blade. Its rather easy to do. the hardest thing being pick-pocketing a key off ether the jarl or his steward.