Combining Big Brother Mentor and Evil Mentor

My most recent creative writing effort has the would-be antagonist's Big Brother Mentor as an Evil Mentor and the real Big Bad.

The basic setup is that the "Big Brother" character (let's call him Alex) is a nigh-immortal demigod who's been Brought Down to Normal. Alex wants to kill the Goddess responsible for this as revenge, but he lacks the power to do so. He needs a human that bears the Goddess's blood to do so, but he's never found someone who he could manipulate into doing so. Until he met our would-be antagonist (let's call him Bob) at a young age. By a gimmick of fate Bob has both the a diluted strain of the Goddess's blood and sufficient reason to hate the nation the Goddess protects. Over the course of a decade, Alex plays the role of Big Brother Mentor to groom him into becoming a leader who will destroy both the Goddess's country and the Goddess herself. To this end he exploits the types of tropes you would expect of this character in a shounen anime, up to and including faking his own death to strengthen Bob's resolve against the hero's party. Eventually, the thread gets pulled and the truth is revealed. Upon realizing that he shares a significant connection to The Hero and realizing he's been manipulated, Bob pulls a Heel–Face Turn and becomes the Deuteragonist.

This is all well and good. What I want for advice is on the characterization of Alex after The Reveal and his interactions with Bob.

• Should I make Alex genuinely care for Bob (as their goals are aligned up to the reveal), or is it better to have Alex treat Bob as a failed tool or disposable pawn?
• And what of Bob? Bob considered Alex to be his brother in all but blood. What should he feel? Hatred and contempt? Sorrow and regret? Determination?
• Also, how much of the heroes' anger be redirected from Bob to Alex after this? Aside from an irrational hatred for the main character, Bob's been an honorable, moral, and well-intentioned character who began to let his desire for revenge overtake what should have been his goal (liberation of his people). I don't want the hero's party to outright hate Bob for the remainder, but I don't want them to forgive him automatically either.

One last question: has this combination of Big Brother Mentor and Evil Mentor been done before in fiction? If so, can you tell me which so I can see how the dynamic between the two characters could play out.

Refer to them as "Alex" and "Bob" in your posts if you would. Those aren't their real names but they're good placeholders as I'm not 100% decided on their real names yet.

Sorry for long post. Just looking to bounce ideas off of someone and looking for advice. Cheers!

edited 7th Jul '17 5:01:22 PM by HijackThis

Hmm, the main character and quasi Big Bad of my story in progress have a similar relationship as Bob and Alex. With Caleb and Zane I went with them legitimately caring about each other, but with Alex and Bob I don't really know enough about them to give a definite "should". My advise would be to think of all the advantages of each option and decide with that.

As for how the rest of the characters respond to Bob, that largely depends on what kind of people they are.

Bob cares about Alex.

Alex ages very slowly and is a humanoid demigod (not human like the rest of the cast is). He's lost his ability to manifest in his true divine form because the aforementioned Goddess feared his power and sealed it away. Alex has spent the better part of many centuries manipulating the rulers and populace of the Goddess's nation and its rival as revenge. Bob's appearance has offered him an opportunity to destroy the Goddess herself. Due to past trauma, the fact that he outlives humans, and his own arrogance, he views humans as pawns. The only reasons he'd make an exception for Bob is for the aforementioned purpose Alex intends for him and because the two have almost identical backstories.