Reckless pretentiousness and porn overthinking ahead:
Kamino Ryu-ya's interpretations of the HnG cast are always strangely compelling for me. What seems OOC if looked at on the surface is actually a surprisingly faithful (albeit disturbing) interpretation. Here, we have what I like to call Ryu-ya's "Damaged Goods/Man Whore" Hayate. Allow me to explain. Hayate's a male lead in a harem series who is generally well-liked and often deserving of the admiration and affections of his female acquaintances. He's also a guy with a LOT of girl issues due to his past relationship and his constant abandonment. A lot of the girls who like him, rather than being doormats with bad taste (like most harems in other series) generally care for him and would go the extra mile for him if he let them (which he tends not to). Hinagiku is probably the best example of this. Now, what we have here is a guy who's had one bad relationship with a girl and for the most part has been kicked around his entire life by people who didn't appreciate how awesome he is, a guy who constantly thinks the people who currently care about him hate his guts due to the most trivial of misunderstandings. We've also got a group of girls (particularly Hinagiku) completely intent on trying to break through this barrier of misunderstandings because that's just how much they love him.
So, I'm saying he has trust issues. Also, the girl he liked in the past was once friends with Hinagiku, and in similar ways to how Nagi regards Hina, Hina sees herself as vastly inferior to the girl Hayate was once intimate with. Trust issues, two people with inferiority complexes, one constantly testing the other to see how much they're willing to endure, one constantly trying to prove just how far they'll go, and we arrive at the Kamino Ryu-ya interpretation.
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For all those of you who read this far, or simply want a tl;dr version: Hayate and Hinagiku? Bondage? I can DIG it!
Seriously, check out Kamino's other HnG works if you haven't. They're definitely intriguing to say the least.