On Being A Game Master: Saying Yes

I'm very grateful that my store's Adventurer's League for DnD 5th Edition is growing.  We've moved from 1 table to 3 in a fairly short period of time.

While I was enjoying playing in Ben B.'s game, the third table was a group of excited player's who were new to the hobby and I felt like I should be the one to guide them into our hobby.

I'm not trying to be vainglorious, it simply seemed that part of my job was to be the guy to introduce them to DnD.

A shortage of DM's was also a factor :)

Since I didn't have much time to prepare a session and I'm not terribly fond of Hoard of the Dragon Queen, we simply made characters.

At the end of character creation, I was overjoyed to see that every player had a name and goal for their PC.

One of player's goals was to find a light saber so that he could defeat the necromancer who killed his brother.  A purple light saber, in fact.

We all laughed and I pointed out he really wanted a magic sword and the player happily accepted this, as we were "playing DnD, not Star Wars."

Except we are playing DnD and why can't there be light sabers?  This occurred to me on the drive home.  I meant no disrespect at my earlier answer to the player, but why couldn't he get a light saber?
How would that break the game?

I'm an experienced enough DM that I don't mind saying "yes" to something and seeing where it goes. I'm philosophically geared to the game being about the players, especially if those players are brand new.

There is no need to filter my preconceived notions about what fantasy is in a game with trolls, vorpal swords, and Tiamat.

In short, the game isn't about me, its about my players.  Wether you call them wizards or jedi, its all just magic.

And in thinking about how that player could could get a light saber, I realized that his nemesis, the necromancer, could in fact be a Dark Lord of the Sith...