One side effect of Manjushri's draining of the lake was that the snake gods called Nagas, which lived in water, were left with no place to live.
Manjushri used to be at war with the snake gods. 
mnli hypothesis: Manjushri used to be at war with the snake gods.  premise: One side effect of Manjushri's draining of the lake was that the snake gods called Nagas, which lived in water, were left with no place to live.