A Side Note
I want to point out something kinda neat/important.
Season 2 is named Shadow & Might.
If we take these as keywords that describe Ninja and Centurion, then this might also help begin to shed light on future seasons and their respective heroes.
Season 3 is named Glory & Wild, and Season 4 is Instinct & Discipline.
Taking into account that a possible hero, the Highlander, was teased weeks ago, that might be Season 3′s Wild aspect.
However, there have also been rumors stirring on reddit that people have been allowed to tease the rest of the heroes. If you want to hear about them, read under the line. If you don’t wanna ruin the surprise, then you can ignore this.