My reaction to the story....
Spoiler:I did not see Rain coming when he was mentioned nor Mavado. Rain made sense given the Osh-Tekk's weakness to darkness. Mavado was just flat random.
I knew it when as soon as Kotal ordered his father to go after Reiko that he was going to be the "major loss" for Kotal. I remember some people thought Erron Black would be the loss.
Mavado is far from random. In the last comic they referenced that they made an alliance with the Red Dragon.