UA: Riddler (http://riddler.io/about.html)
Robots.txt: yes
Looks like either a distro bot or botnet. So far coming from:
Amazon (server farm)
54.72.0.0 - 54.95.255.255
Amazon (server farm)
54.192.0.0 - 54.255.255.255
Sonera (broadband Pool)
88.195.0.0 - 88.195.255.255
Nianet (server farm)
130.185.128.0 - 130.185.143.255
Hetzner (server farm)
176.9.0.0 - 176.9.255.255
Very aggressive despite eating 403s. 3 days hourly non-stop so far.
