Questions answered by Varreon

When you enter the area with Fafnir, run past him and go to the other side of the big rock. Position...

CHeck out their facebook page. This metions it. http://www.gearsofwar3beta.net/

Its in his dome. Just make sure you're standing in the right location.

Try Cultists Tower

http://www.youtube.com/watch?v=drWxoFdqee0

Try using a glaive.

http://www.youtube.com/watch?v=JP9_DmQvvdM

http://www.wikihow.com/Catch-a-MissingNo-in-Pokemon-Red-and-Blue   There you go.