Sozo can be met for the first time at spore grotto, in the big mushroom building at the back. This area is unlocked after a random encounter with the Mushrooms in Anura.

When you first meet Sozo you begin his mushroom quest, he'll ask for 10 menticide mushrooms which you have most likely already gathered after your time in Anura. Completing this will reward the player with a dark talisman fragment.

Sozo will then ask for 20 more menticide mushrooms, upon delivery you unlock the brainwashing ritual and another dark talisman fragment.

After performing the brainwashing ritual you will be rewarded with another dark talisman fragment and the mushroom sculpture blueprint.

After building this decor and making the pledge - can only be done at night time - Sozo will reward you with the final dark talisman fragment.

After talking to Sozo in spore grotto he will tell you that he's eaten a massive amount of mushrooms. Upon visiting the grotto again some time later you can find his body, from this you can grab a 'sozo seed' which can be planted at your cult to re-grow Sozo as a cultist.

Sozo will ask you to rescue his mushroomo friend from Anura, if this quest is completed a mushroom follower will join the cult - this will not unlock the mushroom form - if Sozo finds the mushroom follower he will eat it. His requests for more mushroom followers will continue, if denied he will begin to dissent.

Upon fully re-educating him you will unlock the mushroom follower, and reveal Dr. Sozonius' past.

His appearance and name will also change to reflect this.