What Makes a Good Filler Episode

Filler is treated like a chore between the important arcs, something to skip on a rewatch. That reputation is mostly earned, and yet the best standalone episodes are quietly doing something the main plot cannot.

A good filler slows down and lets a side character breathe. It asks what a hero does on an ordinary afternoon, and the answer often tells us more than another grand battle would.

The trick is restraint. When a standalone episode knows it is a small story and commits to that scale, it becomes a favorite rather than a detour.