Or Aurthian knight AU, in which Ace and Marco are knights of the round table under king White Beards command and, one day they are both sent out to get rid of a slave trade that had sprung up around the area. Ace goes undercover in the slave trade and he finds out that the traders are looking for a key, one that opens up to a mythical world which everyone only hears rumors about. As soon as Ace has the information Marco breaks him out, only to find that Ace has been drugged and in need of a powerful antidote, after killing all the slave traders and destroying their business he finds out that Ace can only be cured by the tears of a mythical Phoenix that people have only heard rumors of. Marco, takes care of Ace while also searching for the key to the mythical realm, It isn't long before Marco turns out empty handed and Ace is dying, Marco starts crying over the loss of someone so important to him and his feelings trigger the Phoenix inside and Ace is cured by Marco's tears.
Both of them return home and there is a party and Ace finds that he now has the power to control fire, Marco is happy for him and it isn't long before Marco starts to want to have Ace as his mate, Aces power is making the Phoenix inside Marco want to jump him every time he lets out him flames, it isn't long that Marco and Ace have to go out and dispose of a pack of hunters that are killing horses that turn out to be unicorns, Ace and Marco turn out sharing a tent and Ace casually tells Marco that he loves him not expecting his feelings to be returned.