Apparently without her armor she considers herself naked even though there's nothing to hide.

Zettaru is a character that I made half a year ago or so and she is a soul infused Artificial Intelligence made by Niko

When infinite life began for Niko (after his mortal life) he felt like he was lonely when thinking about how he will outlive everyone.
So that was the reason he started creating Zettaru.
He performed several rituals to recall Naomi's soul and then put her inside the AI network, she didn't mind it at all.(She can leave any time she wants)
And that's sort of how Zettaru was created, she doesn't mind living with Niko forever and she loves him.
Because Zettaru is an AI network, she can get into any CPU that is powerful enough.
She can use a nearby quantum supercomputer to significantly improve her AI power.
The whole point of her is that now Niko and Zettaru can live together forever.