The series 'Netorare Fighter Yaricchingu!' follows the sexual degradation of Satoru and his devoted girlfriend, Rumi. When a demonic entity transforms Satoru into the lewd hero Yaricchingu, he's cursed to fight interdimensional monster girls. These 'fights' are brutal, non-stop sexual encounters where he's forced to fuck the creatures into submission, filling every one of their holes with his cum until they are completely overwhelmed. Each victory, however, comes at a terrible price. The sexual energy unleashed is siphoned off by the true villains, who use it to sexually corrupt Rumi. She is systematically broken down, forced into increasingly depraved group sex scenes with monstrous thugs, her mind and body given over to pure lust. The series climaxes in a torrent of explicit debauchery, showing Rumi being gangbanged and thoroughly used while Satoru is forced to continue his own series of relentless, pornographic battles, his seed spent on monsters as his true love is defiled.