The falling Illias, all that tells one big story:
Spoiler (Highlight to read):
The Triforce can grant anyone what he/she desires the most. It's so powerful that it can turn even the noblest into foes (Link running for it), friends against each other (Illia about to stab Link, then he kills her), Him standing amongest the Dark Links and the falling Illias represent that Link has to watch out, because if he lets his desire to have her back overrun him, he'd be no better than Ganondorf or any other greedy person who would do anything to get what they want.