These paper models are the World Eaters and Blood Angels Dreadnoughts, based on the game Warhammer 40K, the papercraft was created by Patoroch. There are other Dreadnought paper models at the site:
Warhammer 40K – Dreadnought Mk I Free Paper Models
Warhammer 40K – Chaos Dreadnought Walker Free Paper Models
Warhammer 40K – Mk IV Furioso Dreadnought Free Paper Model
Warhammer 40K – Ultramarines Dreadnought Mk. V
To be entombed within the armoured sarcophagus of a Dreadnought is the greatest honour a Space Marine can be afforded, for even though his body may have been broken, his mind and spirit remains in the service of the Chapter, his Primarch, and the Emperor.
Most of those who are entombed in such a manner are Veterans, line officers or company captains, warriors who fell at the front line. Very occasionally, another type of warrior may be interred - a Librarian, whose fearsome psychic potential remains even after his body is ruined. Librarian Dreadnoughts combine the firepower and armour of a Furioso Dreadnought, enhanced by the abilities of the Librarian entombed within.
The Librarian’s mind is a terrible weapon in itself, able to unleash fearsome blasts of raw Warp energy, seething arcs of etheric power and waves of dread that blast the enemy’s morale to ashes. Some Librarian Dreadnoughts substitute one of their Power Claws for a Force Blade, a large, Dreadnought-grade weapon laced with a network of psycho-conductive material through which they are able to focus their psychic powers. The point of impact is torn asunder as the bonds of reality are severed by the force of the Librarian’s mind and his mastery of the Warp, and few types of armour are proof against such a potent and arcane weapon. Librarian Dreadnoughts are amongst the most revered of all the Chapter’s ancients, and even the most experienced company captain heeds their words of counsel.
It is nearly unheard of for Blood Angels Librarian Dreadnoughts to serve in the Deathwatch. This has only occurred under nearly unique circumstances, notably when a Librarian has fallen whilst standing the Long Watch and a Dreadnought body has been available in which to inter his ruined remains. Most Battle-Brothers who fall in such a manner are of course returned to their Chapters, but on a handful of extremely rare occasions the Librarian has insisted he remain at the Watch Fortress, his wishes expressed not through burned and bloodied lips, but through mind speech communicated directly to his brethren. The spirits of such warriors are invariably so indomitable and mighty that not even the Watch Commander would gainsay their wishes, and the wounded hero is interred within a Dreadnought so that he may continue to stand his Vigil until it is over and his remains may be returned to his home Chapter. Some choose to remain long after their Vigil is completed and their Apocryphon Oath discharged, slumbering for centuries on end within the stasis-sealed vaults at the heart of the Watch Station until such times as they are required to fight once more.
The Blood Angels are one of the 20 First Founding Legions of the Space Marines and were originally the IX Legion before the Second Founding broke the Legiones Astartes up into 1000 separate Chapters. They are well-known across the galaxy for their bloodthirsty nature in battle, and feared for the curse of flawed gene-seed they carry. The Blood Angels are amongst the longest-lived of the Adeptus Astartes, with some of the Chapter's Space Marines having served the Emperor of Mankind for over a thousand standard years. Thanks to recent events, the Blood Angels' numbers have been severely depleted. Under the threat of extinction, and in order to quickly replenish their numbers, the Blood Angels were forced to ask their kindred Successor Chapters from subsequent Astartes Foundings for a tithe of warriors from the related Chapters' pools of Neophytes, their candidate Space Marines. With these tithes of new recruits, the Blood Angels were able to replenish their losses, though they still face a time of trial like none the Chapter has known since the days of the Horus Heresy.
The World Eaters are one of the Traitor Legions of Chaos Space Marines who now inhabit the Warp rift known as the Eye of Terror in the Imperium of Man's Segmentum Obscurus. The World Eaters, originally known as the War Hounds, were also once the XII Legion of the twenty First Founding Space Marine Legions, and one of the first to betray the Emperor of Mankind for the service of Chaos and the Warmaster Horus. This Legion was a collection of nearly inhuman monsters long before Horus became corrupted and monsters they would remain, only with what little remained of their restraint and their humanity stripped away after their fall to Chaos. The World Eaters are now the dedicated servants of the Blood God Khorne, the Chaos God of War and Murder, and live for nothing more than to spill blood in his name. The World Eaters' Primarch, Angron, was one of the first of the Space Marine Primarchs to join with Horus when he turned against the Emperor and began the Horus Heresy. The Legion is no longer united, having long ago surrendered to the pure bloodlust inspired by their patron Khorne and instead they now operate as separate warbands of Chaos Space Marines who seek to spread death and terror in the name of the Blood God across the galaxy. [Source: wikia]
You can download the paper craft model here: Warhammer 40K - World Eaters and Blood Angels Dreadnoughts [Box] [Gavitex]