Why does the doctor have companions

The grief of his fellow time travelers was so great that, for the one and only time in its history, Doctor Who 's end credits rolled in silence to emphasize their sorrow. Another companion who suffered at the hands of the Cybermen was Bill Potts Pearl Mackie -- albeit in a more direct fashion. She was converted into a primitive version of the emotionless cyborgs, leaving her fighting for what little humanity she had left.

She was thankfully rescued by her love interest, Heather, leaving her metal-infused body behind to explore the cosmos as a sentient oil creature.

Nevertheless, her departure depicts the horrors of Cyber-conversion better than any prior episode of the show. The fate of Peri Brown Nicola Bryant is both horrific and confusing in equal measure. She was seemingly killed during the part epic "The Trial of a Time Lord;" her mind erased and replaced with that of the monstrous Kiv before he is destroyed in her body.

However, the end of the serial suggested that Peri had avoided this death and become a warrior queen instead. In the special, despite the destruction of the Bowie Base on Mars being a fixed point in time, the Doctor chooses to change things and save lives.

This is a clear example of the Doctor ignoring the rules imposed by the Time Lords and taking full control for himself. However, Adelaide, who was one of the lives saved, commits suicide to set the timeline right again. It's through Adelaide's actions that the Doctor realizes that he was wrong because, without that fixed point in time, Adelaide's granddaughter wouldn't have become inspired by her grandmother to become an important pioneer of space travel for Earth.

And the action could have pushed the Doctor into becoming more like the renegade Master. In Rose, the Doctor found a person he relied on for her help in adventures, sure, but also someone he connected with romantically, emotionally.

She gets massive points for taking a dip into the time vortex, nearly killing herself in the process, and for managing the Doctor in his transition from Nine to Ten. And lest we forget, poor boyfriend Mickey! Left in the dust by a dashing time-traveling alien.

When he gets his timetable mixed up and shows up over a decade late, he meets a different Amy, an older, more cynical Amy who was told her magical raggedy man was only imaginary. She has a mean streak born out of her defensiveness and occasional insecurity. But Amy and Rory, as a duo, make up the perfect companion — and a totally unique one at that.

In fact, the begrudging boyfriend is its own trope in the show, best represented by Mickey Smith and Danny Pink. The idea of the Doctor being accompanied by another Time Lord is certainly an interesting one, and Romana definitely lived up to expectations.

Mary Tamm did a wonderful job of bringing the character to life, and though she ended up leaving the show after just a single season, her lasting impact on the Whoniverse can still be felt today. There have been numerous iterations of Romana in the years since Tamm's departure, both on the small screen and in the series' many spin-off novels.

The hunt for the six segments of the Key to Time and the showdowns with the Marshal and the Black Guardian were easily the character's best moments though, and serve as a great advertisement for a more involved companion. Leela, or The Lady, as she's often referred, joined forces with the fourth Doctor during his visit to the Face of Evil and helped him to put a stop to the corrupted supercomputer, Xoanon.

She starts out as fairly primitive, though spending more time with the Doctor allows audiences to see another side to the character. That said, Leela's use of force to get things done is something that sticks with her right to the very end; much to the dismay of the Doctor. This does make her an excellent bodyguard though, as evidenced by her time traveling with the second version of Romana a little later on. For a series that's renowned for celebrating campiness and diversity, it's perhaps a little surprising that Bill was the first openly gay companion to travel with the Doctor.

There's far more to the character than just her sexuality though, with her strong personality arguably being her defining feature. Bill didn't spend as much time with the Doctor as some of the series' other companions, but she was still able to squeeze in a few excellent adventures. The climax of the tenth series is particularly memorable, with her and Heather ultimately getting their "happily ever after" moment following several episodes of chaos and uncertainty.

While many of the series' best companions tend to have their best moments with their second incarnation of the Doctor see Sarah-Jane, Clara, and Rose , Captain Jack Harkness is at his very best while alongside the ninth Doctor. The similarities between Jack and Christopher Eccleston's Doctor lead to some excellent moments, but Jack is a brilliant character in his own right. John Barrowman's was the first non-hetero character to appear in the series and was a big hit with audiences due to his no-nonsense approach to adventuring.

This led to him returning multiple times throughout the series after his initial departure and also becoming the lead in the hugely popular spin-off series, Torchwood. Martha Jones joined the show just before Rose's departure and is with the Doctor for some of his lowest points.

Her unrequited feelings for him were a bit of a distraction at times, but they did at least lead to some real personal growth. She really blossoms into her role as a companion over time, demonstrating plenty of heroic qualities along the way.