Toji is first made out to be the bad guy in the story, as he beats on Shinji for hurting his little sister in the first episode. What he doesn't relize at this point is that he saved Tokyo-3 from destruction, thus the victions, Toji's sister, was well worth total destruction from the third Angel.
Later on Toji and Kensuke become good friends with Shinji, also Toji likes Misato as well but is ignorant of how much of a mess she actually is. Misato on the other hand would rather have nothing to do with him. Hikari, the Class Rep, does like Toji, and tries her best to show her affection, by first offering to fix him lunch from the leftovers she has.
Eventually Toji is selected as the 4th Children. From what we can gather he really is not excited at all about this, probably Kensuke would have been a much better choice since he dreamed of becoming a pilot, but Toji was selected. Also it is pretty clear he only would pilot EVA if his sister was transferred to NERV's hosipital where she could get the Medical Treatment she desperately needed.
Toji was selected to pilot Eva-Unit 03, an American made EVA. During the activation tests something went terrible wrong, an angel was able to take over his Eva, and thus Eva-Unit 03 was now targeted as the 13th angel, Bardiel, which must be destroyed. From this engagement there was a huge explosion with many deaths, but Misato and Ritsuko managed to survive.
Apparently all communication was lost between Eva-03 and the command center, thus we can assume Toji was not the brains behind the angel. When faced with this situation Asuka and Rei were quickly beated by Bardiel as he rampaged to Central Dogma, the target for all angels eventually.
Toji's fate was at the hands of Eva-01, synchronized with the dummy plug. Shinji could only watch as his Eva ripped about Bardiel and smashed the entry plug with it's powerful hands. Toji did not die though, as we see him in the hospital, when Hikari visits him he is alive, but if you look at the covers that surround him, he seems to be missing a leg or two. Not much is ever said about Toji again in the series.