The mad titan, and the destroyer of worlds. Thanos has gained quite a cult following in the Marvel comic fandom, thanks to an exceptional motion-capture performance by Josh Brolin in the last two Avengers films. Initially, in the comics, he hadn't been this menacing as he wished to acquire the Infinity Stones and the gauntlet which holds it to impress Mistress Death.
But with further storylines, we have seen the true side of Thanos. He's a practical being who believes that populations need to be balanced out once in a while to solve global crises. However, this gives him no guilt in wiping out any being who comes in his way.
Love: Mistress Death
Let's get back to where it all started. Mistress Death or Death in the Marvel Universe is a woman who embodies all destruction and was apparently created by God. She was charmed by Thanos right from a pre-adolescent age when he was a purple boy (that set him apart from the rest of his family) suffering from Deviant syndrome. She posed as a young girl in his school. She kept his secrets and helped him get over his fears as they grew up.
Theirs turned out to be a toxic romance as she made Thanos realize that he is addicted to murder. Thanos eventually accepts this and starts razing planets to satisfy Death's bloodlust. In one story arc, she finally reveals her true form to Thanos as a skeleton, and says that she's 'the only being in creation who could love you back.' When Thanos destroyed his own planet Titan, that's when she first kissed him. She's an all-powerful mistress indeed!
Despise: Doctor Doom
The archnemesis of Fantastic Four, Doctor Doom has been emerging as one of Marvel's strongest characters over the years. He has powers like energy absorption and dark mysticism. Further, the armor which he wears grants him superhuman strength and a variety of gadgets. He's convinced that this will be enough to make him the ruler of the world. He has often engaged in feuds with Thanos over control of the Infinity gauntlet.
Recently, in Doctor Doom #3, he is even sent straight to hell for various executions but not punished as Thanos's ladylove Mistress Death intervenes. She, instead, sends him back to the universe as her 'most loyal servant'. Definitely, this boon by Mistress Death would increase his power and only add more fire to his battles with Thanos.
Love: Annihilus
Annihilus is the ruler of the Negative Zone, an antimatter parallel universe in Marvel Comics. His most famous appearance was in the 2006 Annihilation storyline, in which this character led the attacks of Annihilation Wave. This series of attacks were directed at various cosmic being from Nova to Silver Surfer. Annihilus took a liking towards Thanos as the latter agreed to be his sidekick during the Wave.
It's amusing to see Thanos play the underling as we are usually accustomed to seeing the purple, bald-headed, titan bark orders while sitting on his chair. He had been of great help to Annihilus as he also helped capture Galactus for him.
Despise: Galactus
You take away someone's food and someone's bound to get angry. That explains Galactus and Thanos's enmity. If Thanos destroys planets, Galactus consumes planets to maintain the cosmic order. He eats worlds both literally and metaphorically. In the Infinity Gauntlet saga, Thanos begins mocking the gigantic 'Devourer of Worlds' by destroying planets that were on his banquet.
Angered by his actions, Galactus joined forces with cosmic heroes like Adam Warlock. On ordinary days, Galactus would not bow down under anyone's leadership. But one can make unconventional choices when in hunger! Thanos later captured a weakened Galactus in the Annihilation crossover event, as mentioned before. That only made Galactus despise the titan more.
Love: Mephisto
Mephisto looks and acts like the Devil, and is fashioned after the Biblical depictions of Satan. His origin is unclear but we mostly find him selling and torturing souls in what seems like Hell.
Mephisto is tempted to get his hands on Thanos's gauntlet and rule all realms himself. Therefore, he shows his attachment to Thanos by claiming that he's related to the creator of the Infinity stones and would help in providing the titan with some secret knowledge around the gems. Mephisto even tries the glove on himself even though the glove attempts to kill him. To this, Thanos feels that Mephisto was only duping him. Despite this incident, Mephisto continues to show his readiness to become his servant. You know you're powerful when even the Devil bows to you!
Despise: Tyrant
In a classic case of 'like father, like son', Galactus's son Tyrant too despises Thanos. A similar feature among all three characters is their desire to take over planets and destruct. While Thanos and Galactus indulge in this cosmic destruction in a balanced manner, Tyrant just engages in large-scale destruction for the thrills.
He's so crazed with his power that he went against his own father. It's therefore not surprising to figure out Tyrant's hatred towards Thanos too. The two even engaged in a duel which ended with Thanos teleporting away with an orb that contained Tyrant's energy. Later, Thanos discovered that the orb contained only a fraction of his energy and Tyrant is a much bigger universal threat than he expected.
Love: Primo
Primo is a self-proclaimed god of fire who often sides with Thanos because it was Thanos who granted him this power. He belonged to the Plasmagen race. When his ship was attacked by Thanos's forces in Avengers: Celestial Quest, the warlord offered Primo his life if he decided to serve him.
And Primo did agree to offer Thanos servitude. Pleased with this, Primo is offered fire-based energy. This also means that he can create and shoot plasma bolts. Primo stayed loyal to Thanos till his very death.
Despise: Ronan
Ronan's storyline with Thanos was explored in detail in the first Guardians Of The Galaxy film. Initially, the Kree warlord works under Thanos as they both wish to destroy the planet of Xandar. A treaty between the Kree and Xandar seems to be underway but Ronan sees peace as an unacceptable option. All through the movie, Thanos often barks orders at Ronan as if he is his minion. But Ronan takes all the orders with obedience as he feels Thanos is the only key to his destructive goals.
Thanos, in fact, uses Ronan to obtain an orb that contains the power stone. And we know what a stone aficionado our purple giant is! When Ronan realizes the power that the stone can yield, he turns on Thanos deciding to use the stone himself to destroy Xandar. He fails eventually but it's interesting to see Ronan rebelling against Thanos. Such betrayals are very common for Thanos and hence, he finds it difficult to create alliances with villains who are perpetually loyal to him.
Love: Proxima Midnight
Proxima Midnight is one of the most significant members of the Black Order. The Order comprises of many intergalactic aliens like her who serve Thanos. Their duties include finding the Infinity stones and defending their Master if any heroes attack him. Thanos claims that he's one of the most powerful beings in the universe and still why does he recruit such minions, we'll never know.
However being the General of the Black Order, Proxima is no ordinary minion. Her power is such that she even pinned down Hulk with her spear. She appears as one of Thanos's adopted daughters in Avengers: Infinity War, as she fights various heroes like Vision and Black Widow.
Despise: Loki
The Norse god of mischief annoys heroes and villains alike and definitely doesn't like anyone who comes in his way of trouble. Rather than brute force, he relies on magic and his own cunning. He too wished to gather the Infinity Stones like Thanos but often failed at his attempts.
In the movies, we see him being held at death point by Thanos who knows that Loki has the Tesseract with him (which contains the Space Stone). Loki might be villainous in the Marvel Cinematic Universe but even he believes that Thanos's plans to take over the world would cause chaos for all realms. So, he decides to not reveal the Stone. He ends up dying at Thanos's hands to the dismay of many fans. But thankfully with Avengers: Endgame changing all timelines, we know that Loki is alive now and will get his own Disney Plus series.