Dear Staff and other members, how do I properly add this credit?

Hi IMDb Staff.

I worked on the movie "Quasi." I played two different characters. I was a King's Guard, who had dialogue. I was also a different King's Guard, who was an integral part of a scene where I laughed, then did a stunt. Both would be considered main cast. Listed on the call sheet and contract as King's Guard #2.

I was credited on screen.

In the scene were I have dialogue, I was not named. In the scene were I laugh, I was given a name (Arnaud) by another character in the scene and referred to by that name.

How should I credit it? 

Should I credit as this ....?

Cast: Arnaud / King's Guard #2

or simply

King's Guard #2

or neither?

And with attributes or without?

PS, many cast members played multiple roles on this movie. Thanks for all help and advice. Below are screen shots.

PPS, as Arnaud, I had a mustache. As the other Guard, I did not have a mustache.