Quality of sculpts 4
Character selection 3
Playability - 4
Overall - 4

A theme I'm not familiar with having never read any of the Marvel Secret Wars series.  The sculpts are solid, but I'm not sure about character selection, simply because there are lots of characters I don't know; that could be a good thing or a bad thing.  Generally most figures are fun to play.

Thanks to Avenger: Infinity War, Thanos is now known to all comic fans. The Mad Titan who wishes to impress Mistress Death by gathering all the Infinity Gems and then wiping out half the population of the universe.

The comic differs from the film; The Magus, the dark personality of Adam Warlock, seeks to conquer the universe. In doing so the Magus creates twisted duplicates of Earth's heroes, and a duplicate of Thanos. However the duplicate of Thanos was an exact copy who would advise Magus in his twisted plans.

Wiki - Thanos_(Doppelganger)
 

On the world of Crystalium the the brothers Crystar and Moltar chose Order over Chaos to oppose the The Demon Lord sent his demon armies.

Wiki - The_Saga_of_Crystar

After the Multiverse was destroyed by incursions, and recreated in the form of Battleworld, MJ and her family found themselves in a domain known as the Regency, fashioned from the remnants of Earth-18119 by the iron will of God Emperor Doom.

Wiki - Mary_Jane_Watson_(Earth-18119)

Annie Parker is the daughter of Spider-Man and Mary Jane Watson-Parker.
After the Multiverse was destroyed by incursions, and recreated in the form of Battleworld, Annie and her family found themselves in a domain known as the Regency, fashioned from the remnants of Earth-18119 by the iron will of God Emperor Doom.

Wiki - Anna-May_Parker_(Earth-18119)

The Outriders is a race of genetically engineered humanoid creatures with the purpose of serving their maker until they die.

Thanos used Outriders to find new planets inhabited by weak species he would raze. Upon finding a new world, an Outrider would report to Corvus Glaive, who would arrive to that planet along Thanos' Black Order and demand a tribute for Thanos, if the inhabitants refused, that world would be annihilated.


Wiki - Outriders_(Race)

The later Bushmaster lost his limbs in an accident and had them replaced with bionic arms and a snake-like tail in the place of the lower half of his body.
Feeling an outcast he later became a member of the Serpent Society.

Wiki - Bushmaster

 

Not much is known about Thorus, but he was originally from the domain of Egyptia. At some point in time, Thorus became a member of the Thor Corps, a force composed of multiple men and women dedicated to preserving peace across Battleworld.

https://marvel.fandom.com/wiki/Thorus_(Earth-51910)