alliy with yourself

[Rough Touch]

I had a game this weekend and my friend had 3 HQ choices 3 troops and 3 heavy's all from the same codex (CSM) he said he can do this as he can ally with the same army as hes playing.
he's prob right but there is nothing in the rules about this and I was thinking some army's would not do this ( I play orks) there would not be 2 different war boss controlling the army as im sure one would not let the other control hes troops ( even though you can pick 2 with normal hq choices)

So
does this mean I can also have 3 HQ choices if I roll 3 x ten grot mobs? I would like a warboss weird boy and big mek ...but it does seem like hes bending the rules a bit

[Deadlift]

The new space marines codex allows you to use your primary detachment with a secondary from the same codex with different chapter tactics. So for example you could take an Imperial fists army with Lysander and an Imperial fists Libby as your main HQs and then allie in some Salamanders with Vulcan.

[Rough Touch]

hmmm well he was playing CSM, not only that they was all nergle. I don't even know if nergle have derachments!

[Amaunator]

CSM and Space marines and Tau can ally with "themselves" easily so that it looks like the units are from the same codex, because their supplement codexi (or in the SMs case, their own codex) has so similar units. Eldar are a bit different, because while Iyanden supplement is Eldar codex as well, the units are all wraiths so there could be a visible difference in units.

CSM+Black legion supplement would be the way for CSM to ally with itself, BL-part of the force has the exact same units available CSM has, but they have to be upgraded if possible (cultists cannot, while marines must) and they have a different items available for characters.

Withouth a supplement or a special rule in codex (Space marines have the special rule, and soon a supplement, most armies don't have either of those yet) you can't ally with yourself, and you can't ally with yourself even if you have a supplement (SM is an exception) but you'll have to use the supplement. Eldar+Iyanden is OK while Eldar+Eldar isn't, Tau+Farsight enclaves is OK while Tau+Tau isn't, CSM+BL is OK while CSM+CSM isn't, SM+SM is OK.

[Tushan]

hmmm well he was playing CSM, not only that they was all nergle. I don't even know if nergle have derachments!

If the primary or allied force was using the black legion supplement then he's all good, otherwise no he cant. The only reason marines can is because each chapter lineage is treated as a separate codex for allied purposes.

If one force was an allied/primary black legion force then every model in it with the option to take veterans of the long war has to.

[Deadlift]

hmmm well he was playing CSM, not only that they was all nergle. I don't even know if nergle have derachments!

To me it sounds like he was just allying himself and using the codex twice. No he can't do this.

[Gotthammer]

To me it sounds like he was just allying himself and using the codex twice. No he can't do this.

And if you do it too much you'll go blind.

[Deadlift]

And if you do it too much you'll go blind.

Oh er mrs, you just went all "Carry on comedy" on me didn't you

[Bob821]

Was it a 2000pt battle? He may have taken to FOC's this would allow him to take the extra HQ and Heavy’s. Of course he must also take an extra 2 Troup choices!

[Rough Touch]

1500pt game
sorry whats a FOC?