Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 17 - 17-4. Purple Mound

Pain, Pain, Go Away is a novel by Sugaru Miaki, also known as Fafoo, author of Starting Over and Three Days of Happiness. Unlike Miaki’s previous two books, Pain, Pain, Go Away is not a rewrite of any story posted to 2ch, but an entirely original one.

The plot involves a young man who becomes a killer (by accident) – but his victim has the power of “postponement,” temporarily delaying her death.

My biggest achievement is not the first person in the entertainment circle, nor the teacher of all people, nor my wealth and status. My proudest achievement is that I live the way I want, not just Live the look that others want – Ye Guang.

- Description from Novelupdates

As a successful villainous BOSS, in addition to having ideas and aspirations, one must also keep in mind three points:First, grow sneakily, don't act rashly (once a villain acts rashly, they basically won't survive past three chapters).Second, you're not a good person, so be ruthless (becoming more evil will make you three times stronger, while redemption weakens you by seven times).Third, remember the two points above. The moment you forget them, your end is probably on its way.