roland and durandal build

[Nosta]

so my first campaign is wrapping up
the final battle is a foot and sides have been taken
The final boss is a demigod lich who has turn an entire plain to the phylactery (did this for plot reasons)
and the good guys have finally gathered the best warriors through out time to help fight with the three player characters

each player character chose three heroes from history/myth
and one of the one chosen was the paladin roland the user of the famous sword durandal

this is high power game
and I was planning on a level 18 build
I need to get the ideas on what type of build should roland be and I need help
building durrandal as a greater relic weapon

can some one help

[noob]

Give it a +5 or more then add in maybe give it the power to be thrown at kilometers.

[Uhtred]

Now see, I read "Durandal" and immediate assumed http://marathongame.wikia.com/wiki/Durandal_(AI) the axe-crazy universe domination-obsessed Artificial Intelligence from the venerable old Marathon franchise that preceded Halo, and I got a bit excited about a rampant AI in a D&D setting.
Moving on. Historically, Durandal is Keen (The sharpest sword in all existence), Holy or Good-aligned, possibly Righteous (Given to Charlemagne by angels), Speed (Roland held off 100,000 Saracens, this would help him get the extra attack a round he needed to do that), and made of Adamantine (the blade is "indestructible"). Add all of that to a +5 longsword and you've got a very powerful +10 weapon that does many of the things that legend claims the sword does. As far as relic features go, maybe give the sword a 1/Day Righteous Might as long as the wielder is using it to defend the innocent in the service of God? Or Shield of Faith +5 1/Day in the same conditions? IDK how powerful you actually want it to be, but operate in the understanding that a weapon is only as strong as its wielder; if your player is likely to make use of special abilities like that, flavor them so that he will want to, but will only use them in dire need.
Roland is obviously a Paladin, given that's the name given to all of Charlemagne's knights; they originated the term. That being said, Roland himself probably had a few Knight Protector levels, since he definitely had the Shining Beacon and Mighty Cleave class features, possibly even the Retributive Attack feature that is the capstone of that class. Having built a Paladin 8/Knight Protector 10, I can say with confidence that the build is capable of doing what Roland could do and more (Short of lobbing the sword with such conviction and desperate strength that it imbedded itself forcefully into a cliff wall, and unretrievable by anyone)