[Lingo] 悪党ども、海賊ども

[steven smith <sjs@example.com>]

I bet you can't guess from the subject what I'm trying to
read :)  (correct answer: space opera manga)

悪党 crosses to scoundrel and 海賊 crosses pirate.  But I'm
not sure what ども is.  It looks like a suffix that makes 悪
党 into "a bunch of scoundrels" or "a band of scoundrels."
Likewise, it looks like 海賊ども is "a bunch of pirates" or
"a band of pirates."  It almost looks like ども is like だ纔瘢韭絎竢蹠\xC2
癈 蜴 友達.  But I'm not quite sure.　

Is this the same ども as 「共」(大人共, 餓鬼共, 事共, etc.)?
 If so, when is it be appropriate to use the Kanji rather
than the Hiragana?

What's the explanation?

Thanks
Steve S.