Onigiri Online: NPC Partner Kaguya ~ All You Need to Know About Games

Kaguya

If you converse with Kaguya, you will get the following three conversation options.

Magatama Crafting

The "Magatama Crafting" option allows you to craft all sorts of magatamas with varied amounts of physical and magical defense, strengthen slots and a variety of different bonus effects.

* The higher Kaguya's "Magatama Crafting" (ネ申製作) ability is, the more kinds of magatamas you can craft and the better your chances of crafting high "Grade" magatamas.
** Just like for "Weapon Crafting", if you ever find items bearing a scroll-like icon and has these characters 勾玉 in its name, please visit this option as it is likely to be a new magatama recipe for Kaguya to learn.
Magatama Decoration

The "Magatama Decoration" option allows you to "customize" your magatamas by inserting various sorts of "Decorative Options" into them. Provided that the magatama has some "Strengthen Slots" that is...

Basically, the entire process somewhat works in a similar fashion as when your performing a weapon over refine. However, instead of using another item of the same name, as a catalyst, you will rather need to procure some "ingredients" which will be consumed by the procedure.

First, select the magatama that your intending to decorate. Next, choose the decorative option you wish to insert into the magatama and then make sure you have the necessary "ingredients" prepared. Finally, put in some "Support Items" to boost your chances of success or protect your magatama (if any) and then go ahead with the whole thingy once your comfortable with it.

Just remember that each strengthen slot may only hold one decorative option. Furthermore, the decorative option can only be inserted if the magatama satisfies the option's "Purity Requirement" and is of the allowed types (refer "Type Requirement" in screenshot).

If your successful with the insert, you will see some sort of confirmation window with the corresponding changes to the stats of your magatama (like as shown above). If unsuccessful, then you will likely break the strengthen slot (and can no longer insert any decorative options into it) or worse still, get your magatama destroyed.

* The higher Kaguya's "Magatama Decoration" (ネ申装飾) ability is, the more decorative options that you will have access to and the better the stats that those options give.
Magatama Disassembly

This option allows you to disassemble any unwanted magatamas that you do not wish to keep and recycle them back into ingredients.

If I'm not wrong, the ingredients that you will get back can likely be used in other places such as for magatama crafting or magatama decoration. However, the kinds of ingredients and the quantities that you can retrieve depends upon the level of Kaguya's "Magatama Disassembly" (ネ申解体) ability.