Actually, you can become his master but you'll need to defeat him many times. I don't remember how much though. Maybe almost a dozen times?
And yes, I agree that the sizes do get a little too much. I reached almost 13 meters in height, and my male tool was about 24 meters with the "eggs" beneath it around 41 meters! That was quite insane. But then I had to have sex with a thirty or maybe fifty-something cobra?
Don't get me wrong, I liked the game very much and especially the story. But maybe it needs some balance? And I also hope we get to do something fun with Abel. Or is it already available and I didn't make the right choices to achieve that?
Nonetheless, sorry for the long tirade.