>>7505040For what it's worth, here's Faber's own words about Takanuva and Terry and their logos:
"When light clashed with darkness in 2003 in the caves beneath Mata Nui it was marked by these logos and nametags. They had a hint to the bigger story. The fact that they fit together is very in line with Bionicle mythology like the jing-jang logo. Takanuva had to merge with Makuta to defeat him. Light and darkness are connected and Makuta actually did god by securing that only the right heroes reentered the giant robot to restart it. Just like the body actually grows stronger and more immune after a virus."
The film's ending is clearly a sloppy mess of half-realized ideas, would be nice if we ever got the true story behind it, but I doubt even the creators remember their original plan at this point. The best I can piece together is that Makuta wasn't intended to be fully evil, but was instead influenced by powers beyond him ("My duty is to the Mask of Shadows"), and removing his mask and fusing with Takanuva somehow purified him, at least momentarily. And only a being born out of the most powerful evil and most powerful good character had the strength to lift up the gate and lead the islanders back into the giant robot.
Of course this last idea was completely nullified in canon, since someone else had to lift up the gate again for them to go back to Mata Nui and then back down again, making Takutanuva's sacrifice pointless. Like I said, it's a mess.