Monochrome: Teito Ninpouchou

This is a tale of modern-day magical ninjas. Reito is just an ordinary guy, who wants to maximize his own happiness by being cool and not thinking of others. However, his stupid, annoying, large-breasted neighbor Iona Shiragami keeps trying to be his friend. One day, he discovers that Iona is more than she appears - she's a ninja who guards a powerful family secret, and other ninja are targeting her for it. When Reito finds himself caught up in her dangerous world, his life takes an unexpected turn that will change everything he thought he knew about himself and those around him. Now entangled in the hidden world of magical ninjas, Reito must navigate new challenges and mysteries while dealing with the consequences of his new reality.