What happens when the God King is defeated?

Spoiler:

When you defeat the God King, he explains that he was the only thing stopping creatures even more powerful than he from coming after you. This sets up for the additional chapters planned, where you delve into the dungeons of the castle to fight the Titans.

Additional spoiler:

After the credits roll, there's an additional cutscene where you find a control panel on the God-King's throne that activates a hologram of a planet with a shattered moon orbiting around it. The character advancement screen then appears, and the next bloodline begins. You don't find out anything more about the hologram.

Video spoilers:

See the ending and the after-credits cutscene on YouTube.

Also, you get an achievement.

there are other strong opponents to kill once you get the infinity blade.