Diagonal Cut-in Brace Removal?
That brace is almost certainly not needed. Diagonal lumber braces are an outdated method from back when walls were sheathed with individual boards, and not with modern structural sheet goods. Also, modern, sheathed and engineered truss roofs provide substantial diagonal bracing where it didn't exist with hand-framed rafter and board roofs. You don't say what era your home is from, but I'd guess at least 1980s from the style.

I can't see what your wall sheathing is, but I can see that we're not talking about a major end wall or other area where we'd expect horizontal loading. If the roof structure depends on that short-angle brace in any way the building has other issues, but I doubt that's the case. 

There's my $.02, which is all you can expect from a random guy on the internet. If you want certainty, pay an engineer to stop by.