Kate Todd's (Sasha Alexander) death on NCIS came as a real shock. Behind the scenes, on the other hand, Alexander's exit was perhaps less of a surprise.

As of Season 22 of NCIS, no characters remain from the procedural's original cast. The last remaining, Dr. Donald "Ducky" Mallard (David McCallum), exited NCIS in its 21st season due to McCallum ...