Although a distinctive villain in his own right, Count Grendel is also significant as he was the only adversary The Doctor faced during his search for the missing segments of the Key to Time (“The Ribos Operation” to “The Armageddon Factor”) where his plans were in no way connected to the segment The Doctor was looking for.
A native of the planet Tara – a world inhabited by human-like beings with a unique social structure, operating on a medieval level in terms of class and dress while capable of building highly advanced android duplicates, created two centuries ago after a virulent plague killed nine-tenths of the peasants -, Grendel sought to become the ruler of Tara himself, having arranged for the assassination of Prince Reynart – the official heir to the throne of Tara – and abducting Princess Strella, the First Lady of Tara and the only other serious contender to the throne, so that he could become king himself.
Typically, Grendel came across as a ruthless man willing to resort to deceit and treachery to achieve his goals, such as creating android assassins to take his enemies by surprise. Although Grendel appeared to have a sense of fair play, preferring to defeat The Doctor in an actual duel rather than just killing an unarmed man when the time came to confront The Doctor directly, he may have simply decided that it would be more fun to kill The Doctor that way after all the trouble that the Time Lord had caused him.
Grendel came to The Doctor’s attention when the TARDIS arrived on Tara while searching for the fourth segment of the Key to Time (“The Androids of Tara“). While Romana set out to find the segment, The Doctor decided to take a holiday and do a spot of fishing, but although Romana quickly discovered the segment, matters were complicated when she was discovered by Grendel’s men as she was an exact physical double of Strella, beng taken away in the belief that she was an android before they realised that she had a sprained ankle.
Unaware of Romana’s fate, The Doctor was recruited to repair an android duplicate of Prince Reynart that Reynart and his advisors intended to use as a double to protect Reynart prior to his coronation, following three attempts on his life. Although Reynart was captured when Grendel managed to drug his group, The Doctor suggested that the coronation go ahead with the android instead to give him and the advisors time to rescue the real Reynart while maintaining Reynart’s status as the heir to the throne.
Although the coronation was nearly interrupted by an android of Strella set to explode in front of the new king, The Doctor was able to expose the android in time, subsequently summoning K9 for additional aid. Grendel attempted to lure The Doctor into a trap to eliminate him with a duplicate of Romana but K9 exposed the android before it could kill The Doctor, forcing Grendel to accelerate his plans. With Romana posing as Strella, Grendel intended to force Reynart to marry ‘Strella’ – unable to convince the real Strella to go along with such a plot while exploiting Romana’s social ignorance of the situation as she wouldn’t know who to trust -, before arranging for Reynart to apparently die of injuries sustained during his capture. With Reynart dead, Grendel could then marry Strella himself, subsequently arranging an ‘unfortunate accident’ so that he could take the throne himself.
Despite Grendel stationing himself in his castle, The Doctor was able to sneak in via a forgotten underground passage connected to the moat, allowing him to access the castle in time to interrupt the wedding. While Reynart’s allies stormed the castle after The Doctor opened the doors, The Doctor engaged Grendel in a duel – using some tricks that he had learned from one of Cleopatra’s bodyguards -, luring him up to the castle battlements and throwing him over the edge into the moat. With Grendel forced to retreat, Reynart and Strella were reunited, leaving The Doctor and Romana to collect K9 and depart with the segment.
The Doctor returned to Tara several years later in his seventh incarnation (“The Trials of Tara”), intending to visit his old friends, only to discover that Reynart had vanished months ago and was presumed dead, with Strella attempting to avoid being forced to marry Grendel by setting up a series of perilous tasks for any would-be suitors to overcome. With The Doctor and Bernice Summerfield – currently disguised as a man – forced to participate in the contests, The Doctor discovered that his rival, Prince Augmentio, was an android Grendel had constructed to kill Strella after wooing her, while Benny discovered Oberon, king of the rejected androids left in the forest, who was forced to help Grendel after the Count kidnapped his wife Titania, allowing The Doctor to reprogram Augmentio to rescue Titania.
Although Grendel gained an unexpected new ally when The Doctors old foe the Kandyman (“The Happiness Patrol“) crash-landed on Tara and was repaired by Grendel’s technicians, Grendel’s last-ditch attack on the castle failed when Reynart returned, having been confined in a temporal trap by three witches allied with Grendel before the TARDIS’s arrival damaged the trap. With the Kandyman destroyed by Grendel’s technicians after it threatened to kill Strella, Grendel retreated to fight another day, leaving The Doctor to enjoy his reunion with his old friends.