Title says it all, really. I've been re-reading my Badab War book pt2, and it struck me how the secretive and vicious Minotaurs seem to have a number of Death Guard-like characteristics.
I don't want to spoil the Badab War books too much for people (two words, though: get them) so I should warn you that all of this thread will be spoiler-y about them!
Points in favour of the Minotaurs being a Death Guard successor chapter:
(1) A fairly significant part of the Death Guard, under the leadership of Captain Nathanial Garro, didn't actually join the rebellion against Horus. It seems, then that Garro and his colleagues from the untainted Death Guard, could have gone on to produce untainted geneseed which could, over time, have been used as the basis of successor chapters.
(2) The Minotaurs are a 21st founding chapter. This was known as the "cursed" founding. The Badab War book explicitly states that the failure of the authorities at the time the chapter was founded to name the source geneseed suggests it could have come from a "tainted" source. Note that other chapters from the 21st founding (like the Lamenters) are happy to cite their original primarch.
(3) The Minotaurs are repeatedly described in terms that seem to link their personaility traits to characteristics shared by the Death Guard. They are taciturn, paranoid, gaunt etc. The Death Guard were a pretty miserable bunch on the whole, with Mortarion often described as sounding like he was both paranoid and a depressive. (Probably due to his terrible upbringing.) The Death Guard legion as a whole only cheered up when they turned to Nurgle!
(4) The Minotaurs are described as being utterly brutal and aggressive in combat, and apparently willing to soak up heavy casualties. I seem to recall that the write up for the DG in an old White Dwarf suggested that they too were pretty blase about casualties, and that they were incredibly ruthless and efficient in a firefight.
(5) The Minotaurs appear to be willing to kill Inquisitorial agents to protect any details of their activities. Now a few chapters would do this, but what if such paranoia were caused by their desire to hide their shameful gene-heritage?
(6) The Minotaurs appear to be fanatically loyal to the High Lords of Terra, and are willing to be used as their bully-boys and enforcers, even against other marine chapters. Perhaps the High Lords authorised their creation, and are the only ones who offer them security against the other marine chapters, who would no doubt be itching to destroy the descendents of Mortarion?
But there are points AGAINST the Minotaurs being a Death Guard successor chapter, too:-
(a) The Badab war book suggests that they could be a "chimaeric" founding, hinting that they have mixed geneseed from one or more sources. This is ony offered as a tentative alternative suggestion to the "tainted source" idea. Of course, this doesn't rule out the Death Guard idea completely, but a mixed geneseed chapter may not have too strong a Death Guard heritage.
(b) Why WOULD the Imperium bother with tainted geneseed? It's not as if they're short of ultramarine stock, which is perfectly serviceable!
© The Minotaurs are more of a heavy assault force, a siege army, with strong stocks of armour and advanced weapons systems, plus a near 100 strong Terminator company, a rarity in the 41st Millenium, where terminator armour is very precious. In contrast, the Death Guard were always a solid infantry force, with the basic tactical marine being the basis of all their strategy. So there are differences between the two chapters' approach to war. (Although perhaps the Minotaurs are just better equipped...?)
(d) The supposedly "Death Guard-like" personality traits of the MInotaurs (paranoia, dourness) are not exactly unknown amongst the Astartes, and could easily be shared by marines descended from other Primarchs. (Not many of them are "gaunt," too, though ...)
To some extent the writer, Alan Bligh, is no doubt playing with the fans here, inviting us to engage in this kind of speculation. But the identity of the Minotaur's progenitor is clearly INTENDED to be an intriguing mystery in the same way that, for example, the Astral Claws and Star Phantom's ancestry isn't. We don't know for sure who the progenitors of those two chapters are either, but clear hints are dropped that they are Gulliman and Johnson respectively.
I should point out I haven't yet read the new "Garro" book, though, so I could be onto a hiding to nothing with a lot of this! But...any thoughts, anyone? 