Percolation: Legends is a fanfic of Marvel: Avengers Alliance and its sequel Marvel: Avengers Alliance Tactics by Playdom, taking place in a "What If?" spin-off of the Gerosha Gaming Universe of The Gerosha Chronicles of Dozerfleet Comics known as the Gerosha Crossover Gaming Universe. As with with Percolation, this story is an unofficial crossover with the Marvel Gaming Universe.
As the incursion that allowed Extirpon to come through to Earth-12131 returns and grows stronger, the Marlquaan itself begins to percolate through. The unstable rifts in energies frighten both Dr. Strange and Galactus, who fear that a total intrusion of the Marlquaan will destroy their universe. Desulon on Phaelon recruits himself and three heroes from Earth-G7.2.1: the Gray Champion, Mapacha, and Navyrope to travel with himself and Hea Pang to the "north pole" of their universe in order to aid Strange and Galactus in keeping the Marlquaan confined to a Gerosha Earth. Amidst the battle, several energies clash between the heroes on both ends, the incursion's obsession with percolating, and the Power Cosmic. However, the heroes manage to destroy the incursion - at a price. The Power Cosmic and Marlquaan together produce exact copies of the three Gerosha Legend heroes that accompanied Desulon and Hea. Those duplicates whose originals had a Marlquaan bond become bound to the Power Cosmic to become pseudo-Marlquaanites.
Worried about the ramifications of more Gerosha hero clones on the team, Nick Fury attempts to dial up Lex Philippine for an explanation of what SCALLOP should do in correspondence with SHIELD. Strange explains that with the incursion destroyed, no signal from SHIELD will be able to percolate to SCALLOP. Since the three new heroes are clones and not the originals, their presence on Earth-12131 poses no credible threat to universal stability. Meanwhile, the events in Tactics result in SHIELD having to establish a base in the Savage Land to ward off the numerous other incursions. While a handful of Marvel heroes prepare to do their job, the new Gerosha imports are taken to Agent Opendi for orientation.
Word reaches Agent Opendi's desk that his outstanding performance has allowed him to be promoted to the rank of Commander. He makes sure to include his new teammates aboard his crew in the Savage Lands. As Gray, Mapacha, and Navyrope accommodate themselves to their new existence, the various Marvel heroes slowly start regaining their original voices. Captain America, for example, no longer talks like a cat. However, Fury begins to wonder if his "Don Corleone" voice has now become permanent.
Commander Opendi and Omega Sentinel continue their relationship, which Sif is still bitter about. As Opendi's crew discovers, new incursions begin erupting, leading to potentially more collisions with non-Marvel Earths leading to potentially endless crossover crises. To make matters worse, they discover that some Icy Finger goons have somehow made their way into Earth-12131 and joined forces with Hydra. Said Icy Finger goons immediately set to work trying to re-create all of the Gray Champion's worst enemies: Eqquibus, Chillingworth, Feathertop, Blackveil, and Bosom-Serpent. It appears that Jawknee has also percolated through - or a clone of her. Either way, the Avengers/Sodality Alliance has its work cut out for it.
- Commander Opendi: A clone of Extirpon that was created to stay behind in Earth-12131 as a SHIELD agent. His prowess in the battlefield, even amidst his power glitches in trying to mimic the original Extirpon, resulted in him being promoted to the rank of commander. He gets in on the action whenever he can, but contents himself to let his friends see action more often.
- John Domeck (clone) / Gray Champion: A clone of John Domeck, who is all too eager to help out his new reality. However, he has trouble fitting in with a world with a history so different from the memories he received from his original.
- Marge Ramirez (clone) / Mapacha: A clone of John's flame-running daughter. She considers the Human Torch to be a "show off."
- Vince Finton (clone) / Navyrope: A clone of the original freedom fighter. Since he has no unique powers of his own, he is able to prove his merits for his highly specialized skill set, similarly to Hawkeye.
- Hea Pang: The original Gray Champion's sidekick.
- Eqquibus (clone): A duplicate of the winged, horse-headed monster that John Domeck first battled when arriving in 21st-century Boston.
- Chillingworth (clone): Named after Roger Chillingworth, this creature has a special vendetta against the Gray Champion for defying Icy Finger demands for over 400 years.
- Feathertop (clone): A scarecow-like abomination with various tricks up its sleeves.
- Blackveil (clone): A deadly foe who has a few abilities in common with the Gray Champion. He can also disappear in a cloud of smoke, and is skilled at psychoanalyzing his targets.
- Bosom-Serpent (clone): A snake-man monster with a snake head in the middle of his chest. He can take a lot of damage before falling, though he is slow-moving.
- Jawknee (clone): The mistress self-proclaimed ruler of all avian life. Birds (especially chickens) do her bidding. She is a giant green chicken with the mind of a homicidal maniac.
The Marvel characters whose voices and mannerisms were tampered with still retain a few of their unique problems, with some variation:
- Nick Fury still has the voice of Don Corleone.
- Maria Hill still has a nagging voice similar to that of Polly Mindoche.
- Captain America is no longer a cat, however.
- Dr. Strange can now have a commanding voice if he pleases.
- The Hulk uses product placement in his sentences less often.
- Iron Man still cannot use his high-energy laser without saying: "Imma firin' mah lazor!!!!". When using Unibeam, he changes it to: "Imma firin' mah OVER 9000!!! lazoooorrz!!!"
- Iron Fist still talks like a Mexican luchador stereotype.
- Sif is begrudging of Commander Opendi, since she fell in love with the original and the clone rejected her in favor of Omega Sentinel.
- Thor still has a Georgia/Tennessee redneck/hillbilly drawl.
- Taskmaster still has the voice of King Candy from Wreck-It Ralph.
This is the second work since the original Percolation in which Ciem and Emeraldon are not mentioned much, if at all, let alone central to the plot, in spite happening very close to the timeline for Sodality. These characters, and the other Houston Elites, were left out for purposes of not making family dynamics too complicated.
Some concept artwork was created on Monday, June 23rd of 2014 around 1:51 AM EDT, with the characters' Sims 2 artwork modified to make them appear more like they belonged inside Tactics.