If he was asked what the cruelest thing he ever faced is, he'll gladly answer it with 'fate'. For someone who has died once, he thought that he was freed from everything related to the world—no. He was forced to live once again—but as a knight, he will face it bravely. But because he was, and still a knight inside his heart, he can't do what he wanted to do. That is way, every time his master was mad at him, the knight just nod and kept quiet about it.
When he watched how Sola-Ui expressed her feeling even though his master was there, there is a little bit of jealousy on how she could do that—it made him want to express his feeling although it wasn't right. That's the reason Diarmuid keep his mouth shut, so that he wouldn't say anything that wasn't supposed to be heard by anyone.
Let him by his master side until the end. Although they are different, the feeling of fulfilling his duty and taking the responsibility changed to love. He wants to see his master's smile. Diarmuid doesn't need the love from his master, he just need to see the blonde man happy. Because he realized that he's not worthy enough for the love of his master.
When his master doesn't acknowledge him, it means that he's unworthy. Diarmuid accepted the fact; he'll always adore his master behind his back.
Kayneth Archibald El-Melloi, the ninth generation of El-Melloi and a genius. Probably he lost counts on how much titles his master held. He decided to have the man as his master although his master always refuses him. But he doesn't mind that, he'll prove himself.
He doesn't need anything beside the satisfied smile from his master; it's enough to make the user of twin spears feels like he achieved his goals. There is time; this Holy Grail will continue for a long time, he still has lots of time to—
—but fate doesn't allow him to do that. He died once, but because of this Holy Grail he could experience it once again. For a moment he remembered what he did when no one was looking at him. He touched his master's working table and smiling while imagining things that only happen in his minds. A smile on his master's face, or probably his master asked him to do some something small so he has the reason to talk with his servants? All the sweet things that usually happen between lovers really made him happy.
But those imaginations made the wound hurt thousand times more, not only because his honor as a knight was destroyed, but the fact that he is unwanted. Is this Diarmuid Ua Duibhne really low so that his master prioritizes his fiancée that never care him at all? That always insults him even after Diarmuid asked her to stop? Diarmuid always try to hold his anger, saying that Kayneth is his and only one master.
He cursed everyone in front of him; he cursed fate, everything and everyone beside him. The thing that angers him more is how until the end, he can't tell his true feelings. His little selfish desire, to say that a knight called Diarmuid Ua Duibhne loves his master, Kayneth Archibald El-Melloi.
That sentence will never be delivered, until his body vanished into thin air. Even until the end, the last thing he saw is his master closed his eyes as if he refused to see the Irish knight even though for the last time. His spirit will not rest in peace.
Is it allowed to wish that he'll see his master again in the afterlife? If so, he'll gladly wait until that time.