Your oracular abilities improve as your piety score increases. Instead of gaining the piety benefits associated with any god, you gain the following traits when you reach the specified piety score.
Wisdom is your spellcasting ability for any spell that you cast through these traits.
Sibyl
Piety 25+ Oracle trait
You can cast Commune as a ritual with this trait. Once you do so, you can't cast it in this way again until you finish a long rest.
You also can't be surprised, provided you aren't incapacitated.