Simple.

Ryu's pupils constricted. 

The voice was like the eruption of a volcano and yet it didn't seem as though the Heaven's Warrior had tried to be so forceful. It was as though this was simply its natural cadence. It didn't feel the need to put in effort for such ants. 

It didn't elaborate its meaning, it wasn't overly verbose, it simply spoke two short and succinct words. As for whether others understood what it meant, maybe it truly didn't care. But, wasn't its meaning as clear as day? 

Who dared to fight against the Heavens?