Ninja Slayer is a Japanese anime series from 2015, adapted from a series of novels and produced by Studio Trigger, following a salaryman who becomes a ninja hunter after a tragedy. The phrase is his signature introduction, delivered before he confronts his targets, and it became closely associated with the show's deadpan, stylised tone. Clips of the line spread through anime fan edits, AMVs, and reaction videos, where its polite formality contrasted with the violence that followed. It remains popular because it works instantly as a recognisable entrance cue, even for viewers who have not seen the full series.