i think its vasu, its probably to do with all the business stuff, becoz sujal is the main man of tge business where varun is a minor. then wen sujal signed trhe paper for rishi to be da power iff attorney vasu was angry bcoz varun did not get it.
remember kartic had all the problem wid kashish and sujal but he did not kill n e 1. it was the sly quiet one siddartrh.
now riva is the one to have problems. but vasu on the other hand may be the sly one who 1nts to kill him.
dats how it work wid ekta rite ( everything is reapeated)