Calista had never liked Olivia during their school days. Calista would make comparisons in everything they did.

After discovering that Calvin liked Olivia, Calista took it further by putting herself at odds with Olivia.

Calista joined Marina's side because she wanted to win Marina's favor.

Back then, Olivia was aware that Calista and Marina had put their feet in their mouths.

Still, even if it wasn't for Calista, someone else would've done it. Things would've ended up the same as long as Jef