Whether this is an angle or not, the Undertaker is likely to end his Hall of Fame career sometime in 2010.
The WWE has announced an Undertaker: Rest in Peace Tour starting in November through live events in Germany (see schedules and events on WWE.com)
More than likely, the Undertaker will officially retire after Wrestlemania 26, and his opponent will now be very interesting because he has the best chance of ending the Undertaker's Wrestlemania streak.
However, whether it is Kane, John Cena or Ted Diabase Jr., the Undertaker's streak should never end.
UPDATE: As I expected, it is now being reported that this name is simply a marketing ploy and not an indication that the Undertaker is retiring.