Star Trek: The Next Generation picked up the adventures first glimpsed in the original TV show featuring Captain James T. Kirk and the crew of the legendary starship Enterprise. Their mission was simple - to explore strange new worlds and seek out new life and new civilizations to join the United Federation of Planets.
The mission was a dangerous one, however. Lurking around every corner was another threat just waiting to pounce; some more dangerous than others. The following is a list of the most powerful villains that Picard and his crew ever faced during their adventures.
Professor Moriarty
Few Star Trek: TNG villains were as unique and resourceful as Professor Moriarty, a character born straight out of the Sherlock Holmes novels and set loose from the Holodeck, itself. Somehow the ship's computer managed to create the character with full sentience and awareness of its surroundings.
This was a baffling conundrum, as it called into question the very rights of a hologram to have and possess sentient rights in the first place. Moriarty proved to be extremely dangerous when he nearly caused the destruction of the Enterprise as a threat in exchange for his own freedom. He was eventually outwitted by Picard and allowed to live out a lifetime's worth of galactic adventures inside a portable Holodeck emitter.
The Echo Papa 607
Though not technically a villain by traditional standards of wickedness, evil and malevolent intent, the Echo Papa 607 was an antagonist the Enterprise had never encountered before. It all began when Captain Picard and the crew investigate the disappearance of the USS Drake in the Lorenze Cluster.
Soon, both a surface away team and the orbiting Enterprise are attacked by an advanced weapons system that keeps upgrading itself each time it is destroyed. Picard soon learns that it's nothing more than a sales gimmick designed to demonstrate the effectiveness of the platform for sale to potential buyers. Defeating it was as simple as closing a sale, but it nearly destroyed the Enterprise in the process.
Masaka
This particular villain was one born of mythology and symbolism, as opposed to a fleshly or non-corporeal being. Masaka manifested herself when the Enterprise investigated a rogue comet and discovered a vast alien information archive. The powers of the archive began transforming technological material on board the Enterprise into a conduit for its symbolic manifestations.
This included Data, who's mind was taken over by the personalities of several mythological beings from the alien race's culture. The most fearsome was Masaka, a symbolic huntress representing the sun. Picard learned to defeat her by wearing the symbolic mask of Korgano, who represented the moon. It was a risky bet that paid off.
Kevin Uxbridge
Upon first glance, Kevin Uxbridge and his charming wife Rishon seemed like two elderly humans who would sooner invite one in for cup of a tea than present themselves as galactic threats. However, Kevin proved to be less inconspicuous than he thought after an attack on a Federation colony left only he and his wife as the sole survivors.
When Picard refused to leave them alone, the Enterprise was fired upon by a mysterious alien warship of immense power. Refusing to back down, Kevin eventually revealed his true form as Douwd, an incredibly powerful alien life form that could create facsimiles of ships, vessels, and even the physical embodiment of his deceased wife Rishon. However, Kevin proved to be a villain driven by desperation, rather than evil intent.
The Parasites
This mysterious alien race somehow managed to infiltrate the highest levels of Starfleet Command and run it from the inside out. During the first few months of the Enterprise's exploratory mission, Picard was informed of a conspiracy brewing within the ranks of Starfleet that represented a grave threat.
This would come to fruition near the end of the season when it was revealed that a parasitic lifeform had taken over the host bodies of prominent Starfleet personnel. With the United Federation of Planets ripe to be overthrown, Picard and Riker worked fast to neutralize the Mother creature, putting a stop to a terrifying invasion plan.
Lore
The android "brother" of Commander Data was an almost identical copy, right down to the last minute physical detail. The only thing that separated the two was Lore's odd facial tick, and the fact that he possessed the ability to process and show human emotion. The latter would prove to be extremely dangerous.
Lore was a malevolent evil twin more interested in power and destruction than benevolence and exploration. He set the dreaded Crystalline Entity against the Enterprise before being defeated. Later, he amassed an army of ex-Borg and prepared an invasion force designed to crush the Federation. Thankfully, Lore was put down by Data himself, and never rose again.
Nagilum
The Enterprise crew found themselves the proverbial rats in an experimental maze in the season two episode "Where Silence Has Lease." It was a monumentally powerful creature that could manipulate the fabric of space itself, a feat demonstrated when it swallowed the Enterprise within a spatial anomaly.
Once inside, Nagilum began testing how the Enterprise crew responded to different scenarios and levels of stress. Eventually, it planned to study the concept of death by subjecting a third of the crew to various forms of slaughter. Picard reacted by setting the Enterprise's self-destruct mechanism which forced Nagilum to approach the situation from a scientific standpoint. He eventually let them go on their merry way.
Armus
The first season episode "Skin of Evil" introduced Star Trek audiences to a creature that had never been glimpsed before - a repulsive entity known as Armus. It ended up demonstrating its might by killing Tasha Yar during an Enterprise away mission. Armus was literally the sentient sum of an alien race's entire evil and wickedness that had been cast off and left to wallow alone for all eternity.
The concepts of kindness and compassion meant nothing to Armus, and he viewed any such act as a sign of weakness. He existed only to sadistically torment other races for his own amusement. Armus was physically invincible, but a heroic and defiant Captain Picard managed to defeat it by making it face its own sorrow, loneliness and despair.
Q
It's hard to classify Q as a full-on villain, given the entity's goals and plans for the Enterprise crew. He showed up as a God-like being of omnipotent power in the first TNG episode where he put mankind on trial for crimes against the universe. In reality, this was a test to see if humans had what it took to evolve into a higher species.
Q would pop up several more times throughout the show's run, usually as a trickster who enjoyed taunting and tormenting the Enterprise crew. Yet, for all his ego and apparent sadism, Q had a soft spot for the Enterprise crew, particularly Captain Picard. If it were not for his own brand of tough love, humanity would have fallen to the first Borg invasion.
The Borg
The Federation had faced down a number of foes over the decades including the Romulans, the Klingons, and the Xindi, but they were schoolyard bullies compared to the Borg. This race of uber-advanced cyborgs was on a quest to enhance the quality of life for the entire galaxy, whether they wanted it or not.
The Borg were comprised of the sum of knowledge from countless species and worlds. Each one that fell was absorbed into the collective consciousness of the Borg Collective, allowing them to advance in technological paradigm shifts. So powerful was the Borg that a single Cube vessel wiped out dozens of Federation starships and almost managed to assimilate Earth under its frightening banner.