Complex sentence: The Klingon High Council feared that Starfleet was developing armies of Augments; after gaining access to genetic material from the Augments, the Klingons performed experiments to increase their own intellect and strength.
Split into simpler sentences: The Klingon High Council feared that Starfleet was developing armies of Augments. After gaining access to genetic material from the Augments, the Klingons performed experiments to increase their own intellect and strength.