There are no eyelets on the carbon Defys. So you can’t fit conventional guards. I use Raceblade Longs on all my road bikes and these don’t touch the frame. I don’t know if the Raceblade Long stays will clear the disk brake on the Defy, and the frame is not drilled for a rim brake, so you you will probably not be able to mount the brackets. They won’t fit anything bolt-through either because the stays fasten to the QR axle.
Giant may update their “Defy” mudguards, which fit the alloy frames fine, but I suspect not.
Another nail in the coffin of disk brakes on road bikes 😉