Nope this is in continuity. Damien Wayne was conceived in the Son of the Demon graphic novel.

In May 2007's Batman#666 Damien Wayne WILL become Batman in the future

On another possible future, specifically the Kingdom Come story, may remember Ibn al Xu'ffasch, who fans believe is Damien Wayne, the son of Batman and Talia Al Ghul.

Incidentally Ibn's name when translated into arabic is "The son of the Bat."

It's nice to know that KC characters are starting to make waves in the current storylines.

Yes, we are currently seeing a resurgence of KC characters in DC's Original Universe.

Take a look at the JSA for instance, Starman, Hawkman (aka Northwind, the godson of the original hero), Atom Smasher and Wilcat (who was revealed to be the original's son) are currently appearing.

In Teen Titans, Plastic Man's son Offspring became a member, and now Damien Wayne, the son of the Bat

And its just now after reading this thread that I discovered the Ras's heir Ibn al Xu'ffasch is also Batman's son.. I'm a klutz for missing out this story because I havent been following Dc for the longest time.