I dont understand this expression 'Frankly, so far, so dull' in this paragraph:
'When his father died, he slaughtered his brothers to capture the throne. He then invaded the neighbouring state of Kalinga, killing 100,000 men, women and children. Frankly , so far, so dull. History is littered with corpses on battlefields' (it is about the man named Ashoka)
(from 'History of the world Episode 3 - The word and the sword' by Andrew Marrs)