Delicate operations necessitate delicate instruments. If he had wanted to send in a blunt tool, he could have done so, and gotten little for his time and effort. For this a different set of skills were needed, more suited for exploration than invasion. It required something small and stealthy, finely tuned. It needed to be strong of course, but there was no fear of that, especially considering how ridiculously overpowered he had made it. It could have taken down a captain were the action necessary, so it would survive to come back. Still, the object's excessive delicacy remained a problem, as he suspected it was a natural mechanism meant to correlate with the level of its strength. She could kill you, but would avoid doing so at the expense of her own life. That needed to be rectified.
It took a few extra weeks, but he managed to insert a program that overrode the conscious mind when certain factors were present. "Attack by hollow" served as one of the keys, "attack by listed shinigami" another. This way ensured that were she ever in any serious danger, she could destroy her opponents without even realizing it. That her consent was not necessary was probably for the best.
He went over the steps of the mission with her very carefully, explaining the duties she had to fulfill and at what point she was to return to the shop. Ururu took it in silently as she always did, but he knew she wouldn't forget a word. He had debated whether to send in additional weapons with her, but then had to deal with the problem of decreased mobility. She was already going to be carrying enough equipment as it was, and while she wouldn't feel the weight, the burden of it would eventually slow her body down. In the end, he trusted to her own monstrous strength and the failsafe in the back of her mind.
Tessai had wanted to accompany her, but their own precarious situation and the search patrols still hunting them had given Urahara's arguments enough weight to force him to back down. She was built, after all, so that they wouldn't have to go themselves, otherwise what was the point? Besides, he needed another experienced eye to help him monitor Garganta. No telling what might come out of the thing.
On the promised day, he had polished Ururu to a bright sheen, the redness of her cheeks contrasting with the pallor of her face. For luck, he had even kissed her, slipping in a bit of tongue that might have delayed the situation had not Tessai come in and interrupted with ugly looks. Ururu burned brightly afterwards, watching him with adoring eyes. He stroked her head.
"One final warning. If you ever see this man, you are to depart the area immediately. Do not attempt to engage him, do not respond if he speaks to you. Run, and don't look back."
Ururu gazed solemnly at the photo of the bespectacled man, and nodded. Urahara smiled.
"You'll know you're there by the moon. Once you land, start off in the direction you think best. You already know the conditions for returning."
He signaled to Tessai, who nodded and began opening it. Garganta was an ugly mess of a thing that had taken years to create; now it was time to see if it actually delivered on the expectations. Just getting through the thing would be an achievement in itself. He wanted to be sure one could survive it, much less actually use it. Hence, Ururu's first part of the mission.
The wind pouring out of it was cold and rough, forcing him to keep a strong hold on his hat. He signaled to Ururu that she could begin, and the doll started forward. Standing before the gaping mouth of the gate, she looked so desperately fragile that it was a wonder the gusts didn't tear her apart. But her softness belied the sturdy materials she had been built with, and after a last, lingering look at Urahara, she stepped into it.
"Shut it!" he yelled to Tessai, who heaved and huffed and practically exhausted his strength in closing the hungry mouth. Slumping against the wall, he took off his glasses and wiped the sweat off his brow, accepting the water Urahara brought him with a sigh of thanks.
"Now all we need is an affirmation, and then it's just a countdown." Urahara watched the device on the other side of the room with eager eyes, knowing if Ururu had landed, she would let them know by transmitting a red signal. So far, nothing.
"She's going to die in there and it'll be your fault." Tessai took another gulp of water, his eyes fixed on the device as well.
"I can always build another." There it was, a red flash confirmed a landing. She was there.
Urahara laughed in relief, and sat down beside Tessai. The two men remained silent for a while, until the sound of voices in the upper level forced Tessai to retreat, leaving Urahara alone with his thoughts. When the older man returned, he broke the quiet.
"This exploration of Hueco Mundo had better be worth it. If that child gets killed because of your curiosity, then I'm leaving you, no matter what happens to me."
"Relax," Urahara murmured. "I've made it so she won't get killed, no matter what. And this way, we'll able to get information the others don't have. All those resources, and Soul Society doesn't even possess reliable data on what kind of topography Hueco Mundo has, much less the make-up and composition of its inhabitants. Aizen knows, that much I'm sure of. Now we'll know too, and can take action accordingly."
"You think he's in there?"
Urahara's eyes darkened. "He can't be in there all the time, what with his increased duties and promotion. But he's bound to visit occasionally, and hopefully not while she's gathering data."
Tessai turned back towards the stairs. "If he sees her, he'll know it was you. And I don't even want to think of what he'll do to her."
"He won't kill her. He likes breaking things more than killing them, so he'll probably tamper with her controls and then set her loose. Best case scenario: she wanders mindlessly through the region until her body self-destructs."
"You can go keep her company then," Tessai said hotly, and stormed off. Urahara watched him leave with a sliver of amusement, thinking how strange it was that the two of them should be paired like this, all because of misfortune. War was not the only thing that made strange bedfellows apparently.
Still, it was worth angering Tessai if it meant receiving the wealth of knowledge that Ururu would bring back with her. While he based his arguments on those of strategy, saying his actions were all countermeasures against Aizen, this was not entirely the truth. In his heart, Urahara remained a scientist, and any opportunity to test a hypothesis was a good opportunity. He fairly salivated at the thought of all that raw data.
Standing up, he went over and inputed a few additional calculations into the monitoring device, then decided he had better go up and help with the shop. They really needed some extra hands. He'd look into making some, perhaps on par with Ururu, after she got back.
Switching the lights off, he shut the door and locked it. Though the room remained empty, there were small murmurs throughout it, much like the moans the wind makes in lonely places. Elsewhere, in a desert the size of a world, a small girl trod on alone, a cold moon watching over her as fear ate her alive.