he didn't. The rings that were of full capacity were supposed to be discarded by the eldwas, so they were being kept inside the storage house where defective/broken/dangerous were being stored in.
The three being the idiots that they were, thought the warehouse was where they kept precious items, hence they stole it out of their own greed
Edit: before you ask why it wasn't guarded, it's because the residents of Asora already knew that the storage house is a dangerous place, it was everyone's mishandling why what happened happened
She's the prostitute that he ran into a few chapters back. She was also an adventurer, and was following him into the forest to rob him or to find what he was looking for. When Makoto and Mio notice them they try and stop them, but they escape and follow them to the ambrosia fields, and flat out state they plan on pillaging them. Makoto and Tomoe teleport them to Asora and they at first have Tomoe, then Mio watch over them, but with the Forest Ogres visiting they were stretched thin and Makoto presumed that the Hyumans of that world would be like Humans of our world -- i.e., he didn't expect them to be supremacists and thought the Orcs would be able to keep them entertained, not realizing the orcs keeping them entertained would be offensive to them.
Current chapter stuff:
The adventurers that were staying in Asora decide that all the awesome magical gear that Asora has is wasted on a bunch of demihumans, so they stage a robbery. Several orcs and Mini-Tomoe try to stop them, but the bag of used rings from Makoto's mana suppression system -- basically, mana-bombs -- are spilled, causing a huge explosion. Mini-Tomoe and the Orc guy are fragged, and hundreds of residents are harmed. I think the adventurers were also randomly stabbing people on their way out, too, not sure. The explosion, since it was made of his mana, caused a gate he opened to the hyuman city to reopen, and she's thrown through. Clay Aegis is mentioned, I don't remember that item, but I believe it cracked because she would have died otherwise.
The rest you can see. Somehow he absorbed her thoughts at the time (possibly because she died from clay aegis but immediately came back) and realized how much the adventurers fucking HATE demihumans. So he goes through the portal, uses Tomoe's mist ability, and calmly kills a bitch.
Now. Does anyone know what chapter of the WN this is? Because I have it on my Kindle and I'm kinda interested in how far off it is.
I'm honestly surprised that the hero actually has emotions in this... was about to drop it because he felt so generic.
Now I'm going to keep reading it a bit longer
Beautiful, now I can rest in peace, knowing that our dear Makoto can now go full-on psychopath.
I'll wait till some foolish priestess think looking into Makoto might be a good idea. Hurhur~ Oh! And when some brainwashed kids think it's a good idea to spy and be hostile to Makoto. Oh, wait. There was that Sofia girl that thought it was a good idea fighting against Makoto, right? I take the wait statement back. I can't wait to see that in manga format! Hahahaha~