Isobelle Reddy (ఐసోబెల్ రెడ్డి)
Nisha Reddy (నిషా రెడ్డి)
Riya Reddy (రియా రెడ్డి)
They were raised in Andhra Pradesh, speaking Telugu, so they don't have the middle names frequent in Bengali. They do speak English though. Isobelle is the youngest, Riya the oldest.
They were raised as triplets - a whiny set that didn't have a great sense of time, and were often bored. Their parents still consider them such.
After registering for Aadhaar - all at the same time (15-ish) - Suspicions were raised at SAMMANA. The three had exactly the same biometrics - DNA, which was expected, but also fingerprint and iris patterns, which is impossible for identical twins or triplets, as they aren't genetically based.
SAMMANA hired them in short order (17-ish). At the point they meet, Isobelle & Nisha are secretaries, Riya is office manager where Usha works (35-ish).
They are, in fact, the same person. Isobelle (which she refers to herself in private) is not quite sure at which age she figured it out, but thinks it was during her teenage years. Every fourth night, Isobelle travels two days into the past - so she'll experience a week as
Monday Tuesday Wednesday | Tuesday Wednesday Thursday | Wednesday Thursday Friday | Thursday Friday Saturday | etc.
On Wednsday, Riya is the persona that has experienced a day three times, and Nisha two times. Even in their office uniforms, people use their jewelry to distinguish between the three - an intentional ploy.
Riya can be extremely proactive with the day's problems - while not being exactly in a groundhog day scenario - from her corner office. Which is not perfect protection from paradox, but hey.
The next day she puts on her Nisha jewelry, following up on leads in the office and the drivers out in the field.
The next day it's Isobelle jewlery, for her first pass. of a new day. Tomorrow, for ther, the cycle restarts.
...she cycles beds based on tomorrows roll. Over the years, in fits of insomnia, she's thought she's seen the transition a few times.
Tripura Sundari is on the home temple, yes.