Recruits' morality varies even more than their species. The ideology of the Dark Army is not easily categorised, though its overall conduct stands up to comparison with the other major forces in the War. It does, however, cheerfully advertise itself as a terribly vicious, annoying and merciless pack of cutthroats. Its commander believes in the power of good PR.
Uniforms are mainly black with gold-coloured bits, though various kinds of recruit do not wear uniform.
It is possible that Iceheart actually travelled to a troll-inhabited region with the intention of hiring a particularly fearsome bodyguard for his return to public life. One alternative theory is that he recruited from a group of wandering trolls, several of which are believed to be marauding the countryside at around this time.
It is interesting to speculate on what would have happened had the inception of the Twine Wars not occurred at this time. Before the trouble starts, trollen, goblin and orkin recruits are already turning up in a steady trickle to Applestone (attracted by good working conditions and prospect of craftsmanship/adventure/beating things up). After this, Iceheart scales up his forces dramatically in response to interworld events, once more choosing to recruit heavily from non-human regions.
The rest is history.