The Silver Chimeras Chapter were created during the 21st Founding, the so-called 'Cursed' Founding. Currently they are a severely weak chapter after the incident with the Inquisition.
The Silver Chimeras were one of the most unfortunate chapters created during the 'Cursed' 21st Founding.
When the Cursed Founding was started, many of the experiments that went wrong showed interesting results, allowing those guinea pigs to be the template's for new chapters. One such test subject, a 12 year old by the name of John Issan showed extremely good results. Allowing himself to change his skin from human flesh to a substance as hard of Adamantium that shimmered and changed colour at will, by experimenting with Necrodermis and injecting it in John, but he rapidly became weaker, couldn't focus very well for a few minutes and his health deteriorated every time he attempted it, giving the possibility that if he tried it too much without break, then they could die from the ability.
A few years later they perfected it, although it still made them weaker, there wasn't a risk that they could die from it and they could now Perform other acts while it was being done, as it took less effort to do it . And so after this amazing spread of results, the silver chameleons were born. After a few centuries, The chapter became well known, crushing rebellions, closing warp gates, boarding hive ships, even killing a band of traitorous inquisitors, starting the long hatred between them and the inquisition.
After 2000 years, M 38 though a horrifying curse overwhelmed the chapter, threatening to destroy them, the first time it was discovered was during a honour quest, when a squad of 6 scouts were walking at crimson mountain when 5 of the scouts skin, blood and flesh turned to molten metal, rippling with colours, screaming as it happened. Only 1 scout, called Luther Mcintyre survived, requested some transport and told the chapter master John Issan (the test subject) what he saw, finding out, to his horror that it had happened all over the chapter, and over 150 Marines of all ranks and ages, including; 60 aspirants, 36 scouts, 23 battle brothers, 18 assault marines (7 during mid flight), 19 devastators(6 only partially melted and fused with there weapons, making them essentially, Imperial Obliterators) even commander Ezekiel melted in front of his troops during a speech.
They were extremely secretive about this whole molten skin syndrome (as it came to be known as in later times by the Imperium), believing themselves to be cursed by a chaos god or the C'Tan were Using some sort of magic due to the use of there resources. the Apothecaries worked day and night to find a cure to this defect from consuming and killing the chapter on a few of the veterans and scouts and aspirants (as the oldest and newest members of the chapter seemed the most affected) that stayed behind while the rest of the chapter was busy trying to stop the domination of fire alongside the Grey knights, Ultramarines, Flesh tearers, and a few sisters of battle orders and various agents of the inquisition. it was at this war, the horrible curse of the Silver Chimeras was revealed to the many agents of the Imperium.
At the time the Chapter's Apothecaries and Techmarines were close to curing this abnormality and stopping it from consuming them while the main of the chapters strength was out on campaign lending there strength to stopping Angron destroying the worlds of the imperium. They had sucseeded after dabbling with the same substance as the Mechanicus had done Necrodermis and ended up preventing it from being lethal-making the armour perfectly fit the users body. That way if the Melt-flesh Illness were to strike then it would just stay in place (although it would hurt like anything) and keep the unfortunate from dying from the bizarre illness.
It was speculated that the inquisition never trusted the Chapter, much less now that there numbers were dwindling without any records of losses. And while the chapter were fighting the chosen Khorne berserker's of Angron alongside Avion Christarus. They were losing until several of the Silver Chimeras suffered from the melt flesh, and destroyed lots of the armour in the bargain. However the Necrodermis skeleton's didn't die. Instead the metallic undead monsters grew, slowly at first, but then it shot up in hight. What's more, the arms became wicked looking blades and brutal hammer shapes. Becoming what was known as later as the grave host's of Issan. After learning this, the Avion Christarus and his band of inquisitors fled the battle communicating in to titan about this curse. Thus bringing the fury of the Grey Knights to the chapter for a crime they didn't commit.
(At the moment this article is under construction. please wait for further improvement.)