Orient bone in world space

I’m working on a simple animation for a game I’m making, and there’s a bone that I need to point at the camera. (It’s a viewmodel animation.) However, it inherits rotation from its parent bone, and I want to keep it that way. It would be fine for me to turn the bone to face the camera object, turn it to point along an axis, or turn it to a particular orientation in world space. It seems simple enough, and maybe it’s something that would be completely obvious to somebody who uses Blender frequently, but I’ve been searching for a solution for hours, and I haven’t found any!
That’s about it, I think. How can I do any of these three things: turn the bone to face the camera object, turn it to point along an axis, or turn it to a particular orientation in world space?

Normally that kind of multiple targeting is done by using “TrackTo“ constraint in Pose mode. If you have three targets, you willneed three constraints. Activate constraint as needed with Influencebar.