Anecdotes of Two Sisters on the Other Side

The two protagonists met through each other's mothers when they were young, but later separated due to a quarrel between each other's mothers. Reunion after many years. But there was no time to celebrate in the future, and both parties accidentally fell into the water and were robbed of their lifespan... For each other and for their mother, the two agreed to work in the underworld in exchange for a virtuous lifespan... In the end, the protagonists will get rid of the psychological implications of becoming a symbiote and regain their main body.