If someone were to question anyone from the loose soul capturing squad, Elsie was the lamest one of all of them. She was slow-witted, unreliable and clumsy. Keima couldn't agree more. He said so himself in Elsie's face.
But, if one was to think about it, Elsie can't really be blamed for it. She was always being brought down by her fellow demons that all she can do was just be who she is.
But since she was assigned to be the partner of Katsuragi Keima, the "Capturing God", she was glad. Glad to have a reliable, though reluctant, partner such as her Kami-nii-sama.
Elsie herself knows that she is dumb and somewhat dense. That's why when Hakua came and showed her glory to her nii-sama, she knew that her existence (or what's left of it) was disappearing in the dark-haired otaku's world. She was already disappearing in his world as it is, because of his "conquering conquests".
She can't blame herself for wallowing in self-pity, resulting in crappier results on her part. Always being scolded by his Kami-nii-sama. Always being left out of the grand situations. Always pushed away to the side.
But, she is still a girl. She can't avoid falling in love for the dark-haired boy. Keima Katsuragi, after all, is the first (boy) to be kind to her. Although not many can see it, Keima was always gentle with he; in his own twisted way. So, who can blame her for loving Keima?
But when Elsie saw Keima crying while listening to Chihiro's song, she was slapped in the face by the truth; the truth that her Kami-nii-sama loves her (relatively) close friend, Chihiro.
That night, when she was lying on her bed, all she could think of was 'sorry'. How sorry she is for dragging Keima in the demons' business. Sorry for making Keima have a broken heart.
After she had cried herself to sleep, she decided to keep her feelings to herself. It was for the best. It was only fair (in her opinion) that not only the partner gets a broken heart. It was all she could think of to repay everything Keima did for her.
So, with one last silent 'I Love You', she said to the love of her life "I'm Sorry".
AN: Sorry about the mistake that I made with Chihiro's name. I only realized my mistake when my two gracious reviewer pointed it out for me. Thank you to the kind soul that they was. :D