Don't know if anyone knew already, but there's a trick where you could contract just about any hostile intelligent creature as a companion, particularly semi-megabeasts like giants. Well... sorta. To start, you'd need to have an adventurer with hero status (ie killed at least one night troll or something better), and probably just a kick-ass adventurer overall. Furthermore, you might want to have a site with numerous logs available, if you're looking to build stuff.
Anyway, here's how it's done:
- Find a target. This should be a non-leader historical figure that's at least semi-intelligent capable of speaking, and, preferrably, doesn't have extravision (ie has functional eyes).
- Get outside their vision range and sneak up to them. Or, better yet, blind them.
- Skip introductions and bring up incident of a significant kill you made (hopefully, one that won't anger them further!)
- Ask for them to join
- Should the target get hostile, blind them (if they aren't already), wait around for about a hundred turns or so until they're no longer in combat, then try talking to them as above
And, that should do. Just note, there's several precautions to take. In particular, the target is still hostile to you, and will attack and stop following you should they regain their sight or you bump into their space. Should that happen, just repeat step five. Otherwise, besides spitting at and spiting you, they'll do just about anything else a normal ally will do, including help build a site for you. In the latter case, they seem to cease becoming violent so long as you leave them to that task on their own, though chopping logs, sleeping, and generally bringing up the timer seems to snap them out of that phase.