Spammers are always trying to find new ways to get their links on our blogs. I do not use the comment blacklist because I am well aware that blocking by IP address is useless. IP addresses have not been unique for a decade. ISPs save money by placing hundreds of us in the same IP block. So using the blacklist for IPs means we may block legitimate commenters. Moreover, spammers can get a new IP in seconds flat and some have dynamic ie. ever changing IPs.
May advice is stop wasting you time fretting over a single spammer.
Akismet is a very accurate learning engine. The vast and overwhelming majority of all so-called information on the internet is spam. Over 80% of all so-called comments submitted to .wordpress.com blogs every day are spam. Spam comes in waves. There are human beings who get paid to post spam. There are robotic programs that post spam.
The worst of all spam containing malware and viruses is not sent to us. It's removed as it could bring down many blogs if opened.
On the spam that Akismet catches it takes only seconds to click "empty spam" and you don't even have to click "empty spam" if you don't want to. Akismet will maintain comments it has caught for 15 days from the time they were received, and then it will delete the comment automatically.
If you get spam that slips by Akismet then mark it as spam (do not delete it) and over time Akismet will learn it's spam.
If you find the spam in the Spam folder, then Akismet is doing its job. If you find them in the comments waiting for your approval and you have marked them as spam, then you are helping Akismet learn its job.
There is no such thing as eliminating all spam but Akismet works very well. For more information please take the time to read "5 things every blogger should know about spam" on this page Akismet: How it works http://akismet.com/how/
Note: If the Akismet contact form is not working for whatever reason: email@example.com