The motive behind Hannibal eating people is inconsistent, right? He says to eat the rude, but he also eats people who he feels possessive over, like Bedelia, he wants to eat Alana, likewise, and in his desperation, he wanted to eat Will. This is his expression of self. Love is expressed through consumption, contempt is expressed through consumption. He needs an excuse to kill and eat someone; this is who he is specifically — this is how he ticks. But the most fascinating aspect about Hannibal is that he can stop at any time. He can say, “I will never eat anyone from this day onwards” and he can keep that promise. Because what is extraordinary about Hannibal, what is unique about him — is his self-control. He is, at any moment, faithful to who he thinks he is. If he thinks he wants to kill, he will. If he thinks he wants to nurture, he does. He is only truthful and loyal to himself. And his motives, they are riddled with entropy, and he enjoys the volatility that circumstances cause.
This isn’t all a spiel to say that he is going to abandon himself for the sake of another — in fact, what I’m saying is the exact opposite — and therefore it is what makes his interactions with Will so exhilarating. What he wants has changed in his association with Will, yet his ego still triumps in their every interaction because it is still something he wants. Perhaps his love is selfless, in that he is sacrificing aspects of his life, rather, compromising (but Hannibal doesn’t compromise, so it is a sacrifice), to elevate Will — to purify Will, because he has gradually come to love Will and doesn’t want him to suffer with indecision not for the sake of objective aesthetic, or to validate his philosophy of life and death and beauty, but it’s that he cannot sever himself from Will anymore and therefore has ended up (softly) needing Will to be okay with his inherent cruelty. He has to bring out his beloved’s true potential. This is love. (edit: also, decidedly, for objective aesthetic. Perhaps Hannibal is triumphed in Will’s becoming, even if it means that Hannibal dies, and this, to him, isn’t entirely unacceptable, as well as it is egotistical)
Hannibal is, in essence, playing the game for entirely different stakes. He is someone who enjoys life so much that one simply cannot defeat him. Cannot Kill him. Cannot make him feel the defeat in death. I think Will realises this more than anybody, and that in itself should make him feel defeated.