shivanya married rithik coz she wanted to find out the fifth killer...shivangi's enemies were powerful supernatural creatures who were after her n gautami so after becoming naagin she wanted to stay close to them to find ways to kill them n gautami be safe somewhere...but bela could have easily killed her enemies by now they have no raksha kawach nothing and completed her revenge...this much planning plotting scheming was not needed...leads will marry n fall in love everyone knows it, here question is about story of the show ..