I'm slightly confused by these two. In all of the lead up it mentions hero choices affect if the overlord gets them or what abilities they get. However after looking over the quest book and using them in a campaign the only time I can see them in use by the overlord is in one of the finales and every other time they are under hero control. Am I just missing something here?

The blurb is rather grand-sounding for what actually happens during the campaign, yes.

In Act I heroes control either Serena or Raythen, and they have a chance to reverse their choice during an Act II quest... or the OL might force the switch on them during the same quest, which is one of a total of two quests where you can see Serena/Raythen as a lieutenant. So you got it exactly right.

The blurb is rather grand-sounding for what actually happens during the campaign, yes.

In Act I heroes control either Serena or Raythen, and they have a chance to reverse their choice during an Act II quest... or the OL might force the switch on them during the same quest, which is one of a total of two quests where you can see Serena/Raythen as a lieutenant. So you got it exactly right.

What's the name of that quest?

Fountain of Insight, Act II

Fountain of Insight, Act II

Cool thanks!