Maxim & Selan
Estpolis II's canon lovers are the most serious characters in the game. Given that, one wouldn't think they'd get along with Dekar, but strangely enough, they bond with him in their own ways during their travels.

Of the two, Maxim and Dekar have the more pleasant relationship. It's one of mutual respect. Maxim respects Dekar's superior physical strength (to the point of avoiding a duel with him when they first meet), and Dekar respects Maxim's reputation as a great warrior (to the point of making an excuse for Maxim when he declines said duel). They're comrades in arms who trust each other; they're fellow fighters with strong battle instincts (both have gut levels of 100 by default). During Dekar's silly, arrogant, and pushier moments, Maxim quietly cedes the spotlight to him. It would seem that he's inwardly amused by Dekar's flashy personality.

Selan, on the other hand, isn't quite so amused. She's unforgiving during Dekar's stupid moments, dismissive of his romantic pursuits, and unimpressed with his physical prowess. Perhaps befittingly, Dekar's attitude towards Selan is similar. While he acknowledges Selan's beauty when they first meet, it's the only aspect of her that he ever compliments. He is unfazed by Selan's reputation as a harsh character and powerful warrior. When Selan insists on going with Maxim to fight Gades the second time, an impatient Dekar interjects, basically telling her that she should follow Maxim's orders and stay behind. (He treats her almost chauvinistically, which is ironic, since Selan is very feminist.) Unlike Maxim and Dekar, Selan and Dekar don't readily respect each other. Selan does give Dekar some credit for his devotion to the Prince of Bound, however, and expresses some grief at his presumed passing in Karlloon. But Dekar doesn't get a chance to return such sentiments. Perhaps that's because he never gets to experience Selan's softer side. It's likely that he ended up appreciating her abilities, though, since he battled alongside her for quite a while.

(It would appear that Dekar has more respect for Tia's personality than Selan's. Maybe he feels that Tia's more womanly behavior is more attractive or appropriate than Selan's behavior.)

It's worth noting that, in Karlloon, after Iris helps the party escape, Selan says, "No, it can't be true, that Dekar didn't...". Could it be that she, like so many more ordinary folk, came to believe Dekar's oft-touted belief that he was invincible?