beta
Ok so I read the raws a bit
Basically Parvel knows that Sienna is Sion. When you see the flashback to when Parvel got blessed by God, he had a flashback to when Sion was unjustly killed and how he had fallen in love with Sion in his past life. Parvel then wakes up after being blessed and goes searching for Sion in the current world, however he can’t find him. When Sion (now Sienna) reacted to Parvel for the first time after reincarnating, Parvel knew he had found Sion (in Sienna’s body), which is why he acts much more caring towards Sienna, and why he is overprotective.