Well, this came out of nowhere. While it's been five years since Immortal last released an album, 2009's spectacular All Shall Fall, it may be quite a while until you hear any more new music from the band.
Norway's Dagbladet reports that Abbath aka Olve Eikemo has submitted a patent application for the Immortal logo and name to be the property of Eikemo Compositions, which is his own personal corporation.
Seemingly, he didn't clear this with the rest of his bandmates, because they hired lawyers to petition the patent claim by Abbath.
Nobody has publicly commented on the situation, but clearly things are not healthy in the camp. As MetalSucks points out, Abbath could be doing this with the intent of canning his bandmates and turning Immortal into a black metal version of Guns N Roses. If he gets the copyright claims, that would be within his right.
Ultimately, this it's a big bummer to see business get in the way of one of the biggest black metal bands of all time. Let's hope they can figure this out without causing too much of a mess.