Doggy style, and he notices something.

"Get on all fours," Kazuma requested of Megumin.

"Okay," she nodded, still blushing. She got on her hands and knees, her ass pointing towards him, and he noticed something on it.

"Is that a tattoo?" he asked as he knelt behind her. "It looks like a barcode..."

"Yes... The Crimson Demon Clan all has them," Megumin replied, blushing. "Though not all in the same place..."

"I see," he said as he pulled his cock free from his pants, and lined it up, wondering how he missed it before, though deciding it must have been the lighting in the rooms he'd seen her naked in before. "Are you ready?" he asked her.

"...just be gentle..." she begged, quite the opposite of what he would expect of Darkness. He nodded and slowly pressed into her pussy. She gasped and gripped the grass as he went all the way in, buried to the hilt.

He waited several seconds for her to adjust before slowly pulling out, and then pushing back in. "Oh!" she exhaled as he did so. She bit her lip as he repeated the motion a few times.

"Wow, you're so tight..." he remarked.

"Well, my body is small..." she moaned. "You can go faster now..." He nodded and began to speed up, pumping his hips into her, planting his hands on her ass. "Ahn!" she gasped, letting her tongue loll out. "This feels amazing!"

"That would be the point," he chuckled as he kept going. He continued to fuck her for several minutes, gradually going faster until he was pounding into her. Finally, she screamed out and threw her head back as her eyes rolled up, her orgasm jolting right through her body.

On cue, his throbbing shaft erupted and spilled his seed into her opening. Her front collapsed as she panted, her hips still up against his pelvis until he pulled out, and she laid on her side.