The Umbral Knight is a mysterious dude who wakes Lily up at the start of Ender Lilies. For whatever reason, I could never get a good impression of the Knight’s personality. The Umbral Knight is the more talkative of the two main characters as he(?) comments on all kinds of things. Mostly the areas and bosses. The Knight has a respect for the dead and, well, he’s protecting a little girl…so he’s honorable. I should note though that he did consider killing Lily just before he wakes her up, hoping that it would break his curse. More on that later.
The Umbral Knight’s whole thing is…that he’s one of the Ancients. The original inhabitants of the kingdom before the first king killed all of them. The Knight has an undying contract with a bloodline…the bloodline that Fretia belongs to. Basically, he can’t die/pass on unless that entire bloodline dies out. He’s also forced to stay with members of that bloodline…though I’m not sure of the exact mechanics. So…that’s why the Knight thought of killing Lily though, as we find out in Ending A…yeah, it would have been pointless because Fretia is still alive. After the fact, I realized that the Umbral Knight was keeping his distance from Lily at the start of the game. Though this is very subtle.
His/Her name is revealed at the end of the game, though we don’t know whether the Knight is male or female.