Ekimu is evil.
You can tell because his name starts with 'E'.
Evil begins with 'E'.
Furthermore, Ekimu and Evil share an I, making Ekimu more evil.
Ekimu? More like Evilkimu. And of course, everything he says about Makuta is not to be trusted.
Also, he was sealed in a coffin by the Protectors. What if that wasn't because he was, uh, weak? What if that was because he was a source of great evil and had to be sealed away, and now he has manipulated the entirety of Okoto into reawakening him? Now he is free, ready to unleash his minions, and unleash them, he did.... [MASK OF LIGHT MUSIC]
But seriously, what if Ekimu betrays the Toa?