Kanojo ga Ore ni Kureta Mono ~KISS My Darling:Mecha-con case~ by Onomatope - Adult Sex Game

Mikado is a normal guy who longs for a harem and bringing happiness to all the girls in the world. Since this requires lots of money, he spends every day and night doing part-time jobs. His mad scientist and hikikomori imouto Tsubasa was worried about her dear brother neglecting his studies. So, she created the ultimate sleep-studying device Pandora to help him, resulting in him having lots of information from the net downloaded into his brain.At that time, a beautiful girl Carrot transferred into his class. After hearing her refined greeting, he knew from her name that she was the princess of a certain country. With her true identity suddenly made public, she became really close to him and his surroundings began to change.