legendary sword abilities for katana and wakizashi set

[Kimras]

I'm trying to make it for my samurai as an ancient ancestral heirloom set. That was hidden away and a new set was then handed down his previous weapon set. I want to go all out with this as a reward for actually surviving without his previous heirloom to give him power. This set will have two things I know of shadow striking and the ability to use some wind and sonic magic the thing can be slightly cursed. so thank you if you can help.

[Sir Chuckles]

The best I can say is to look in the book Weapons of Legacy.
That won't give any specific item, but it should give you a decent overview of how a "special" weapon should end up.

[Gildedragon]

Look at devious and vicious: they have a few abilities that get boosted when they are near each other. that is a good first step.

second: have abilities that synergize with each other (one lowers ac for the next one to hit; one is an aptitude weapon keyed to feats that would affect the other)

third: make them easier to use with each other (reduce the TWF penalty by 1 for example)

then add a few flavor things: iaijutsu focus is prolly a skill you are using with these two: make each grant a +1 bonus to the check, a whopping +4 if they are used together, allow them to be quicksheathed if the quickdraw feat is had.

[Shinken]

Since it's a samurai think, you could make the pair allow him to take guidance from his ancestors.
The set could cast some divination spell once per day as the user meditates. Which spell depends on the character's level, of course, but if you choose augury be sure to make it usable more than once a day.
You could also make it so that the user can call onto the knowledge of previous samurai. That could mean he can replace any check with another modifier (maybe his attack bonus or an Iaijutsu Focus bonus) a few times per day, as he uses his combat knowledge/focuses his ki to tap onto the memories stored in the blades.
I read a book once where a samurai had a wakizashi that showed anyone who saw their reflection in the blade a vision of their own death. You could do something like that, you can use it to set up some hooks even, but it gets all the problems prophecies already have in RPGs.
Also, a theme you could run is electricity in one sword and cold in the other. Call the set Heart of the Storm (or Arashi no Kokoro).

[Brunks]

I want to go all out with this as a reward for actually surviving without his previous heirloom to give him power.

What level are they?

I'd say slap a bunch of useful options on there,

I had a few ideas, most based on spells/feats:


According to legend, Masamune’s blades were revered as holy objects, while weapons forged by Muramasa were said to drive their owners to commit evil acts of bloodlust. In one tale, a curious samurai placed the two swords in a river with lotus leaves to test their aptitude for cutting. Muramasa’s sword shredded everything it touched – leaves, fish, and even the air itself – whereas the water simply flowed on past Masamune’s blade.

Katana:

Iaijutsu:
Once per day, as a swift action you can make Iaijutsu focus strike with this sheathed weapon.
With one quick fluid motion you draw, strike and resheath your weapon. This does not provoke an attack of opportunity.

Flowing air:
As long as this weapon is drawn and being held you can sense the slightest ripples in the air around you. You gain blindsight 30ft

Windblade:
While holding this weapon air itself becomes an extension of the blade, increasing your reach by 5ft.

IFF:
This blade never causes unintentional harm. If the blade for some reason strikes the wrong target it will deal no damage if you do not wish it to.

Slashing wind:
Five times per day you can have your attack with this sword be carried through the air, striking your enemy at a great distance (60ft).

Divine Wind
The air bends incoming ranged attacks away, you have 20% concealment against all ranged attacks. While holding the weapon.

Peace:
While this weapon remains sheathed you gain a +2 circumstance bonus on diplomacy checks.

Air Walk:
Once per day you can gain the effects of the Air Walk spell for 1 hour.

Wakasashi
Thirsty:
This weapon thirsts for blood, it threatens on 18-20 and does triple damage on a crit. This stacks with spells and effects like Keen Weapon

Deadly:
The blade always finds the sweet spot that much easier, if you deal sneak attack, skirmish, or Iaijutsu focus damage with this weapon add Xd6 to the total.

Cut Anything:
This blade is sharp, sharper than you can believe. It ignores hardness and damage reduction of all kinds.

Shadowblade:
Once per day as you attack with this weapon you can shift it partially to the plane of shadows, making your attack a touch attack.

Shadowslash:
Five times per day, as an immediate action you can teleport 10ft and make a attack with this blade. You must attack a creature to use this effect.

Oppertune
The blade knows when to strike, spellcasters you threaten still provoke an AOO, even when casting defensively. You must use this weapon to make any attack of opportunity.

Drawn:
This weapon cannot be sheathed until it has dealt damage, while it is drawn and held it gives a +4 circumstance bonus to intimidate checks.

SET BONUS - When both weapons are held at the same time you gain the following benefits.
Reduced penalty on 2 weapon fighting by 2
Electricity Resistance 20
Protection from Energy Drain
Base Speed increased by 10ft
One additional daily use of the swords effects.

[Red Fel]

I would recommend setting them up as Weapons of Legacy, from the book of the same name, but for the fact that the mechanics in that game (actually having to take penalties and the like) make WoLs undesirable. However, there are some homebrew fixes out there; Google is your friend.

Note also that the OA Samurai class (not the CW Samurai class, and note that not all "Samurai" have levels in a Samurai class) gains a double-helping of the Ancestral Relic feat, for free, in the form of the Ancestral Daisho ability. This basically lets your samurai enhance his daisho with whatever powers he wants, based on his character level, which is pretty darn nice.

If you want to go whole-hog, consider making them intelligent items (http://www.d20srd.org/srd/magicItems/intelligentItems.htm), which gives them powers also, or even an item familiar (http://www.d20srd.org/srd/variant/magic/itemFamiliars.htm) (if you're willing to risk the cheese involved).

As for specific powers, it depends what he does with them. I would suggest that one have various defensive enhancements on it, and the other various offensive enhancements. I could give a list, but it's fairly context-dependent.

[zahlfrin]

What level are they?

I'd say slap a bunch of useful options on there,

I had a few ideas, most based on spells/feats:



Katana:

Iaijutsu:
Once per day, as a swift action you can make Iaijutsu focus strike with this sheathed weapon.
With one quick fluid motion you draw, strike and resheath your weapon. This does not provoke an attack of opportunity.

Flowing air:
As long as this weapon is drawn and being held you can sense the slightest ripples in the air around you. You gain blindsight 30ft

Windblade:
While holding this weapon air itself becomes an extension of the blade, increasing your reach by 5ft.

IFF:
This blade never causes unintentional harm. If the blade for some reason strikes the wrong target it will deal no damage if you do not wish it to.

Slashing wind:
Five times per day you can have your attack with this sword be carried through the air, striking your enemy at a great distance (60ft).

Divine Wind
The air bends incoming ranged attacks away, you have 20% concealment against all ranged attacks. While holding the weapon.

Peace:
While this weapon remains sheathed you gain a +2 circumstance bonus on diplomacy checks.

Air Walk:
Once per day you can gain the effects of the Air Walk spell for 1 hour.

Wakasashi
Thirsty:
This weapon thirsts for blood, it threatens on 18-20 and does triple damage on a crit. This stacks with spells and effects like Keen Weapon

Deadly:
The blade always finds the sweet spot that much easier, if you deal sneak attack, skirmish, or Iaijutsu focus damage with this weapon add Xd6 to the total.

Cut Anything:
This blade is sharp, sharper than you can believe. It ignores hardness and damage reduction of all kinds.

Shadowblade:
Once per day as you attack with this weapon you can shift it partially to the plane of shadows, making your attack a touch attack.

Shadowslash:
Five times per day, as an immediate action you can teleport 10ft and make a attack with this blade. You must attack a creature to use this effect.

Oppertune
The blade knows when to strike, spellcasters you threaten still provoke an AOO, even when casting defensively. You must use this weapon to make any attack of opportunity.

Drawn:
This weapon cannot be sheathed until it has dealt damage, while it is drawn and held it gives a +4 circumstance bonus to intimidate checks.

SET BONUS - When both weapons are held at the same time you gain the following benefits.
Reduced penalty on 2 weapon fighting by 2
Electricity Resistance 20
Protection from Energy Drain
Base Speed increased by 10ft
One additional daily use of the swords effects.


This bonuses might be a little bit OP (just a little, lol), if all of them were to be applied on the same set, at the same time; but they make much sense, though.
Once I played a Stonechild Samurai by the book, and it was awesome! If I had any ideas for your Kanata & Wakisashi set, I'll be more than glad to help!
Greetings from Mexico! :D