This is the back ground for my chaos guard

In M41.571 the imperial world of Calderon was told to provide a force for the defence of the Cadian Gate. Calderon was a forge world in the north of imperial controlled space near to where Dark Eldar raided constantly. They mustered 7 infantry regiments, 3 Leman Russ regiments, 1 Artillery Regiment, 4 Sentinel Companies, 1 Light Armour Regiment, 10 Valkeries, 2 Baneblades and a Warhound Scout Titan. They also had around 1,000 political officers.
they were as follows
4th, 5th and 6th Calderon Rifles
8th Calderon stromtroopers
12th Ranger Recon
17th and 21st Auxillary
45th, 76th and 81st Leman Russ Companies
129th Artillery
153rd Light Armour
4 Sentinel Squadrons from the 735th SEntinel company
485th Assualt Armour
10 Valkeries from the Calderon Air Assualt Corps (Attached to the 8th Stromtroopers)
The baneblades were called 'Revenge of Calderon' and 'Malleus'
the Warhound was called 'Enigma'
They were placed under command of Lord General Quintius Orellus
He was given command of a fleet of ships including three capital class ships and four mass conveyance ships and multiple Cruisers and Frigates.
Unfortunatley these ships had been rushed in their production as there was reportedly a mass assualt on the Cadian gate. This meant the warp drives of the ships failed instantly when activated so they let some of the warp seep into all the ships turning all the troopers skin black their minds were also warped by the experience. They realised that the imperium would kill them no matter their intentions. When they exited warp space they ended up on the wrong side of he Cadian Gate. THey didn't realise by this point it was M41.773. Warmaster Abadon's personal forces the first to find them. By this time all signs of the imperium had been defiled and all the priests had been killed. They then pleged allgence to Abadon and his dark gods. Most decided to serve all the gods equally but the stormtroopers pleged themselves to Khorne and Tzeench creating a great rivalary in that regiment. The warmaster in his tactical genius knew about the Sabbat Worlds Crusade and how the forces of the dark gods were being pushed back by Warmaster Macaroth's forces. They were sent to bolster the defences of Anakwannar Sek's forces including the Sons of Sek. Before they left The Warmaster had their ships warp engines repaired. When they arrived adopted the Command structure of the sons and Quintus Orellus adopted the Rank of Etogaur and took the name of the chaotic saint Sho'Va.
Enroute to he sabbat worlds the warp drives were need of colling so they stopped in an area of deep space. While they were resting two Astartes thunderhawks were detected heading towards their position. One belonged to the Ultramarines, under the command of Sergeant Ultarius, and the other to the Space Wolves, under the command of veteran Ulva. They headed towards a mass conveyance ship. HOused within it's great hull was the 5th, 8th, 17th, and 76th regiments. Two Cruisers 'Khorne's Chosen' and 'Beloved is Abaddon' moved up to intercept the Astartes and their ships. The Ultramarines landed weel within the barracks of the 8th regiment were all the troopers were returning from a field drill. There was a short but bloody fire fight with Malal damougaur (Colonel) slaying Ultarius in a duel. Ultarius thought by trying to hold back the Damogaur and his forces his brothers could escape. 7 Marines made it back to the escape pod just in time to see their thunderhawk destroyed by 'Khorne's Chosen'. They were slaughtered by Malal and his retinue. Ulva's forces landed in a canteen were 5th regiment troopers were enjoying a meal. They slaughtered over 200 troopers before Head Slaughterer (Lord Commissar) Gorath who personally slew 6 Wolves and as their thunderhawk was destroyed Ulva was brought down by the fire of 2 eintire platoons. 6 of the Space Wolves were seperated by the mass of bodies in the canteen. Realised they would die if they continued to fight the overwhelming tide of chaotic followers they surrended themselves to the will of the chaos gods as their will pressed against their mind. Ultarius's body was fastened to a leman Russes hull to show what they can do against Astartes when they are the favoured ones.
The baneblade called 'Revenge of Calderon' was renamed the 'Abadonn's Fury'
They then went to fight the imperials wining many victorys in the names of the dark gods , the Anarach and Abadon. They helped destroy the loyalist fleet defending Gereon when the Anarch decided to take it as his own.

In 382 M.35 The White Angels were founded as a successor chapter of the highly honoured Blood Angels. Although they are scions of Sanguinus they were set up by the Inquisitors Grand Master Casophili of the Ordos Maelleus and Master Czevak of the Ordos Xenos. This was highly opposed by the Ordos Hereticus and many Puritan Inquisitors of the Ordos Maelleus. The reason for this was that the gene seed used wasn't purely Sanguinus. It was a mere 50%. Many Inquisitors were shocked to discover that the gene seed conatained parts of World Eaters, Thousand Sons and Space Wolf genes. This means there is a higher amount of Librarians in the Chapter and seem to be blood thirstier than other chapters but less fall to the Black Rage. This project was mainly backed by The head of Ordos Maelleus , Greig Hopfman. The reason for the mixed gene seed was to confuse Daemons as one of the main theroies was that Daemons could detect the gene seed of marines nearby and therefore know whether they were allies or enemies. This experiment was also to try and solve the problem of the red thirst. shortly after their creation the eintire chapter were conscripted to Cleanse a Daemon infested world in the Segmentum Obscurus.

The Angels enbarked on Thunderhawks, Stormravens and Stormbirds along with the 2 strike Cruisers and 5 Frigates. It took them 5 weeks to get from Scintilla, their homeworld, to get to Arqtius the daemon world in question. They were also accommpied by 5 imperial guard regiments and an eintire imprial navy fleet under Admiral Luas. When they entered orbit round the planet the Angels descended without letting Admiral Luas or Lord General Sunajes of the Imperial Guard who watched in amazement as one thousand marines dropped to the planets Surface in Drop pods thunderhawks stormhawks and storm ravens. Reports from the surviving marines claimed the daemons were acting unprepared as the marines emerged from the drop pods as if they weren't sure what ahd just happened. Millions of Daemons were vanquished within the first half hour as the marines slaughtered the confused Daemons. After an hour the imperial guard regiments dropped from orbit along with imperial navy air support. Unfortuneatley daemonic magic defenses were now in place. This meant half of the transports and aircraft were vapourised by daemonic lightning. The surviving craft were flung across the planets surface. 1000 infantry died as they plunged into a sea of daemonic acid. Only 600 infantry and 3 Leman Russ Companies landed at the RV point where the White Angels had focused their Defence. It was the Hive city Indomitus or Ghru'fa'tak as the daemons renamed it. In the center of the hive there resided a Greater daemon of Khorne who engaged a lst dich defence of the hive. He struck down 23 terminators of the 1st company including Captain Gruhan and Lieuteneants Jafal and Suroh as they tried to stop the daemon rampaging through the chapter. he was only felled by Chapter Master Lozrael and Inquisitor Glaedus. Lord General Sunajes aqquited himself very well by rallying 5 Leman Russ Companies and 1500 Infantry troopers and breaking through the almost limitless amounts of Slaaneshi Daemons. 2 Keepers of Secrets and 5 Heralds of slaanesh were killed of which 3 were killed by Sunajes in hand to hand combat. He was eventully laid low just before they linked up with the angels as he was surrounded Daemonettes. When the second wave reached his fallen and crippled body there was over 30 Damonettes bodies lying around his dying body. The bodies didn't disapate as there was still a warp gate open. He lived long enough to see the 7th company of White Angels charge into the rear of the daemons to link up with his now extremly thinned strike force. Eventully after 17 long hours of fighting Scouts managed to located and kill the Tzeench Sorcerors creating the warp storm. The warp strom suddenly dissapated. Now Lozrael called down orbital strikes on the remaining daemons and launched a spearhead to close the warp Gate. It took another 18 members of the first company and 7 librarians to close it but once it was closed the remianing daemons lost the will to fight and were quickly vanquished.

Due to the open possiblity of an action like this happening again the White Angels were allowed to expand to contain an extra 2 Scout Companies, 2 Front Line Companies and an extra Assualt Marine Company.

They also use the rank of Lieutennant unlike other MArine Companies.
The rank of lieutennat is bestowed to the five members of the command squad. This means there is a more structured command structure.

The White Angels are all extremly modest about themselves especially when in front of Blood Angels whom they idolise. Once not long after their battle on Arquitus that they were in a joint action with their forefathers against three ork space hulks. " were quickly destroyed but he larger third one took alot of fire and destroyed a strike cruiser. That was then Lozrael decieded to take on a boarding action. 5 White Angels and 2 Blood Angels drop pods smashed into the ork space hulk. After 2 hours of harsh fighting The MArines made their way to the Engine room. They hid over half a tonne of melta and krak explosives with the timers set for 1 hour. They then broke out in a devastating charge surrendering themselves to the red thirst. the orks were completely wrong footed by the sudden charge of marines. Within 55 minutes they made it back to the drop pods but 3 Blood Angels had been trapped in a side corridor on the way there. Lozrael Then led a counter attack slaughtering over a hundred orks and guiding the 3 injured Blood angels back to the drop pods. They made it back just as the charges detonated. Suddenly the hulk started to disentegrate and the marines just escaped. With the hulk disentegrating the Strike Cruisers poured fire into the cracks of the hulk destroying it in a massive blast