Neopedia

The Mersa Trilogy is a trilogy of three books in the Neomorphs series. It is so named because it focuses around the life of Mersa 528. The Trilogy begins with book 66: he Hunters, continues with book 67: The Loss, and concludes with book 68: The Redemption. The Trilogy is important in that it accomplishes several milestones in the series:
Contains Spoilers

• In the Trilogy, Tobias begins to draw on the Howler collective memory.
• Marco loses his memory.
• Such characters as Menderash and Loren are reintroduced into the series.
• The true nature and purposes of The One are revealed.
• Mersa betrays both the Animorphs and Yeerks.
• The presence of the Pythag and the influence of the Pythagi Conglomerate are revealed.
• Jake is brought back to life.
• Mersa is killed.
• Chapman is freed.
• The Animorphs begin to fear that Tobias, Rachel, Ax, and Al are Controllers.