I remember spending hours rerolling on the day of release, hoping to get both Kai and Vannis at the same time. 
In the end, the day was almost over, and I ended up with just Kai and Espada...
After that, no matter how many times I tried the regular or event gachas, I couldn't get Vannis, so I ended up getting him through a regular exchange...
I took pictures of the scenes that appeared during the reroll challenge.<img src="https://storage.googleapis.com/akuaya-kzj0o/akuaya-kzj0o/admin-console-images/emoji_vanis_regular_nomarl.png" alt="" height="28" width="28" fetchpriority="high" class="mx-2 mt-2 inline-block align-bottom"><img src="https://storage.googleapis.com/akuaya-kzj0o/akuaya-kzj0o/admin-console-images/emoji_kai_regular_nomarl.png" alt="" height="28" width="28" fetchpriority="high" class="mx-2 mt-2 inline-block align-bottom">
I only posted Kai and Vanis, but the other characters' pictures are still there... I'm glad I took the pictures.

Aquaya Memories | Kohaku's post