Break Fluid Disappearing

Hey guys, I have a 2007 Tacoma (120,000 miles) with the 5 speed manual transmission and 4 cylinder engine. I for the life of me cannot figure out where my brake fluid is going. I have to fill it just about once a month. I have no leaks in any of the lines- brake lines and clutch lines . I checked to make sure my wheel cylinders weren't leaking in the drum brakes. Any ideas? The picture below is after not adding any for about a month

 

Have you pulled the master cylinder away from the brake booster and checked there?
I have seen them leak into the booster with no signs of an external leak.
If this is the case you will need to replace the booster in addition to the master cylinder.
It could also be leaking from the clutch master or slave cylinder as it shares the same reservoir.

 

This^^^

If you can't find the leak it is getting into the brake booster and being sucked into the engine. That is why you can't locate the leak.

Or it is leaking inside via the clutch master and soaking into the carpet. But I think you would notice this.

 

It looks pretty dry to me. No fluid that I can see. Any other possible ideas?

 

Did you look at your clutch master and slave cylinder?