i have an idea to start the story
when diablo enterd hell he probly ran into another maiden of pain (Andarial)
:lovedup and then hehe had some fun like any guy that hasnt had it in a few years and then well you get the son of diablo.
it would start with the birth of the son.
and the mercs should be able to be controlled like a 2nd charictor switch back and forth between the two,
you should be able to give them there own stats and abilitys to up grade,
AND BECAUSE THERE A MERC THEY SHOULD BE ABLE TO USE ANY ITEM OF THE CLASS/TYPE THAT THEY USE NO MATTER IF ITS A CHARICTOR CLASS ITEM!.
like the iron wolf he should have been able to use paliden shields because he is a merc.
an idea for other charictor classes one should be SAMARI and other warrior/spell casters that were not used (shaman)
and the old charictors could be the mercs u use :grunt