Okay, so I got a couple ideas here. There are a few directions you can go to. First; you can look at it quite literal and animate some sort of iron armor texture that rolls over the text and forms the final logo. Add some lensflares en some booming sound effects. Done.
However, what I always prefer is a clean intro that stands on it’s own and doesn’t need all that shine and bling to stand out in the crowd. The letters enter the screen (this could be with a layered fade, entering one by one from a direction off screen, etc, etc.) The light line and the star/flare animate in a fancy way and after all is done moving very dynamically you have a brand standing there in de middle of your screen, ready to be printed in everyone’s mind. Since you only have about 5 seconds this is the way I would recommend and still recall after seeing the movie.
So to recap; I would always go for a clean, sleek, simple and strong animation that uses that precious 5 seconds to make sure people remember your brand.
I do this kind of stuff on a daily basis. Let me make this for you :