This Nioh 2 guide will cover what the Sudama wants and some of the nuances associated with them.
Giving the Purple Kodama What It Wants, Including Smelly Round Things
The Sudama want your items, weapons, armor, and Soul Cores. In addition, if it asks for a “smelly round thing,” it’s looking for either a Dung Ball or Noble Dung ball item.
When you encounter a purple Kodama:
Open your inventory Select any piece of equipment, item, Soul Core, or Dung Ball if it wants a smelly round thing Open the item options menu Select the Drop command
The Sudama will do a little dance, pick up your gift, and give you another item in return.
The easiest way to farm smelly round Dung Balls is by killing Tesso yokai, the farting rat demons. You’ll find these enemies starting in mission 9, Bird in a Cage, in the “Shadow” section of the campaign. Once you get to these later missions, find the closest Tesso to a shrine, kill it, run back to the shrine, and reset the world. The Tesso will reappear and you can farm it endlessly.
What You’ll Get From the Sudama
That’s the short version. There’s some nuance to account for, however. Your reward from the purple Kodama depends on a few factors.
First, the Sudama will give you a new item at your gift’s level and will take into account its abilities and rarity.
If give a Level 35 Rare Sword to the Sudama, you have a chance of getting the same qualities in return, with abilities or upgraded stats. You’ll always get the same type of item you dropped: weapons for weapons, items and upgrade materials for the same, and so on.
Giving a Sudama a Soul Core has similar results, though you aren’t guaranteed the same level core. Either way, you could receive a random Soul Core, or you might get a re-rolled version of whichever Soul Core type you drop. This applies to any Soul Core you have, including the powerful boss cores. If you’re in the market for new abilities on your favorite yokai ability, Sudama are your ticket.
If you give Dung Balls of either type to Sudama, they’ll give you a random assortment of consumable or upgrade items. These can be Summoner’s Candles, Books of Reincarnation, Epic-quality crafting materials, and so on.
One final note: once you make it deeper into the game, giant Sudama will begin to spawn. These large purple Kodamas will accept two items and will give as many items in return.
That’s the gist of it for Nioh 2 purple Kodama when it seems as though it wants something or it’s looking for a smelly round thing: find one, give it weapons, items, Soul Cores, etc., get something back for your trouble. Simple, and in a loot game with seemingly limitless options, a godsend.