How would I make a 'Animtrail' onto a sword animation?

For one of my projects, I'm trying to make a "Animtrail" to help the players see the exact range of the sword.

A example I guess would be a shooting star - like how it leaves behind a huge line behind it - so for what I'm trying to figure out is kind of a light-particle that follows the sword's swinging path.

Well, First of all you need to know the position of where you want the particles to start, and end, and you probably should use a "While True Do" so that it keeps repeating, I will try and make one, then show it too you. :)