And just like that, Thanos was everywhere.
He was in Brian Michael Bendis & Mark Bagley's Avengers Assemble; he starred in a mini-series by Jason Aaron & Simone Bianchi; he was the instigating antagonist of Jonathan Hickman & Jim Cheung's line-wide crossover Infinity; and he was in a post-credits scene at the end of 2011's hit film The Avengers.
Where Thanos wasn't was under Jim Starlin's thumb.
The courtesies previously granted to Starlin were now clearly on the skids; creators (such as Hickman & Cheung) had no problem with altering Thanos' costume, sending him after the Infinity Gems again and otherwise treating him as a constantly-restless would-be conqueror.
Starlin hadn't even been given notice that Thanos would be making his big screen debut and it rankled him; fortunately, with all the cash Thanos was bringing into Marvel, there was a little to spread around. Starlin had spent most of his time since the Thanos ongoing working for DC Comics, but Marvel hired him back to run a series of original graphic novels starring Thanos.
The first three novels tell one long story of Thanos battling Annihilus. They are titled: Thanos: The Infinity Revelation (2014), Thanos: The Infinity Relativity (2015) and Thanos: The Infinity Finale (2016). Starlin drew the first two books, but brought in Ron Lim to draw the third (all inks by Andy Smith). Marvel was definitely banking on the combination of Thanos + Starlin + Infinity to once again = $$$$. For his part, Starlin brought in elements from the contemporary Marvel cosmic titles, using the Annihilators and Guardians of the Galaxy teams.
Between the graphic novels Starlin authored tie-ins; first came Thanos Annual (2014), drawn by Ron Lim and inked by Andy Smith; set following Thanos' defeat by Captain Marvel, it has Thanos encounter his future self from The Infinity Gauntlet, who tries (and fails) to enlighten his younger self.
Next came Thanos vs. Hulk #1-4 (2015), drawn by Starlin and inked by Andy Smith; finally there was Infinity Entity (2016) #1-4, drawn by Alan Davis and inked by Mark Farmer. The collaboration between Starlin/Davis/Farmer seemed a happy one as soon after they reunited for the mini-series Guardians of the Galaxy: Mother Entropy.
Just this month, Starlin/Davis/Farmer united yet again for Thanos: The Infinity Siblings, yet another original graphic novel. According to Starlin, this graphic novel is actually setting itself up as the middle part of a trilogy (the earlier Revelation/Relativity/Finale being the first third). How many combinations of 'Infinity __________' can Marvel publish? I suppose we'll find out. The new graphic novel is quite good and, for the first time, shows Starlin taking an interest in Thanos' brother Eros as Eros finally matures and demonstrates some careful long-term planning - and the two brothers are even united in common cause. Starlin once again demonstrated some good faith to other creators as he utilized the costume & thralls Hickman & Cheung had given Thanos during their Infinity.
Starlin remains somewhat short-tempered when interviewers ask him about Thanos, but if he truly means to continue his current storyline over the next few years, I'm all for it. Keith Giffen aside, I haven't found that Marvel has any authors willing to grant Thanos the wit, intellect and sense of wonder that Starlin imbues his creation with. Thanos is best left in Starlin's hands, as other creators tend to simply retread The Infinity Gauntlet (and only the first 4 issues of the series at that).
Very shortly the feature film Avengers: Infinity War will reach theatres. The fortunes of that film will no doubt determine a portion of Thanos' future in the comics.