Overlord: where to start reading
Adapts Overlord by Kugane Maruyama. Say how far you watched, and pick the book up exactly there.
at Volume 14.
After all four seasons the story continues at volume 15. Be aware that volumes 12 and 13, the Holy Kingdom arc, were skipped by the anime and are being adapted as a film, so you have not seen them.
Seasons 1-4 (all aired so far) leaves off around volume 15. Pick the manga up right there:
Volume 15
Faithful here
The show stays close to the book here, with nothing major changed, cut, or invented.
The source is a LIGHT NOVEL, so answers are volumes. Only one stopping point is given here, after all four aired seasons, because the adaptation does not run straight through: season four drew on volumes 10, 11 and 14 and deliberately skipped volumes 12 and 13, the Holy Kingdom arc, which is being covered by a film instead. A per-season answer would therefore be misleading, so it is not offered.
Rate it from where you are. No account, and nothing here says a word about what happens next.
