Gale was an auto include most of the time, especially when deliberately playing an evil party, you need his ability to learn clerical spells. Now a days, I don't even activate his intro and leave that way point undiscovered. The fact that he doesn't even have a tadpole, but seems to know everything about them, how he already understands how a devil thinks, his willingness to read the Thayan tomb, I'm pretty sure I know who he really is. We'll see if I'm right when the curtain lifts in Act 3.
It's pretty clear that Gale has a tadpole: powers, dreams, your initial meeting with him where he speaks of "our problem" etc.
Not sure why you believe he doesn't have one.
