Thanks for your reply!
I'm not really sure if it's dark blue or purple, because the one I tried is quite old and the sponge is almost blackish color. The owner doesn't know what series of whale this is, but he said this rubber is a national version.
Do you have any idea what this rubber is?
Well the only thing I found out is that there was a version of the Haifu Blue Whale III. It was called Haifu Blue Whale III Factory Tuned Training Version:
http://ttnpp.com/store/haifu/477-haifu-blue-whale-iii-3-factory-tuned-training-version-6.html
You can see 2 versions: one with dark purple and one with pink sponge.
And there is a post on another forum about the "new" Haifu Blue Whale III. But this was in 2009:
http://mytabletennis.net/forum/forum_posts.asp?TID=26645
On the same Forum somebody thested the Haifu Blue Whale III with a purple sponge:
http://mytabletennis.net/forum/forum_posts.asp?TID=71413&title=haifu-shark-and-whale-3-forum-testing
Now after some searching it seems like there was a version called Haifu Blue Whale III Factory Tuned Version with dark purple sponge. The thing with "national version" is that some shady people use this to sell their products much easier. So i think this "national version" Haifu Whale rubber your friend got was once a Haifu Blue Whale III Factory Tuned Version rubber sold to as a "national version". This Haifu Blue Whale III Factory Tuned Version is surely a very special rubber since its original price was once pretty high (at around 90$).
The Haifu Blue Whale III Factory Tuned Version comes in with two different color sponges as you can see in the first link. A dark purple and a pink one. But I don't know which color the sponge has of the Haifu Blue Whale III Factory Tuned Version which is still being sold on some sites. You would have to give it a try.
Do you know when your friend bought this his Haifu Whale rubber?