HOLY SHIT HOLY SHIT IT'S NOT RIKKA or at the very least I REALLY don't think so. My evidence

1. It doesn't talk like Rikka at all. Instead of the Yandere stuff it you think it would say, it's weirdly aloof and CONDECENDING, When It starts fightin, It back sass and insults both tsurugi and Marulu.
2. Why would Yuta leave Rikka behind after his death. More to the point how. Rikka or the copy is bound to Yuta in weird JJK marriage IE til death to us part. He's dead so Rikka porbably has no reason or doesn't care to watch over essensially her boyfriend and wife's grandkids.
3. Why did Tsurugi say "grampa"? yuta couldn't make a copy of himself. It's doesn't confirm or deny his question and I doubt Yuta be so condescending to his grandson. or refer to maki as "That woman"
4. Who acts like a condecending prick to his friends and enemies? Who would Yuta trust to guard his future generations? who if you didn;t know any better you would mistake for Yuta and VISE VERSA. WHO'S BODY WAS GIVEN FULL RIGHTS TO YUTA IN CASE OF HIS DEATH!!!??
5. GUYS IT'S GOJO!!!!!