This event Demonic Soul has 208 or 206 total characters in the soul pool.
Here's some info on the odds.
I opened about 10 souls and got nothing but 3*.
As someone else mentioned, in this BoS event, I too already opened a bunch of souls yesterday, which could have possibly dropped today's event souls if only I had known to wait.
Great event planning, Devs.
(Actual image of Navigator Games. Looks like their planning out the month with events, or maybe planning on who's bringing cups, ice, chips, cookies, pizza, ice cream, and bacon... etc., to this years Christmas party.) 🤣