Hadn't noticed this on the TT map till earlier today.
Sorry if I'm slow on it, normally I don't pay attention on stuff like this, but being a map that's rectangular and having "empty" space on the top and bottom of it, noticed some of the decor when I was looking at some match history. Maybe the lighter colors there as compared to the darker ones on the actual in-game map made it easier to notice? http://i.imgur.com/qMIAtQ3.png
so on the bottom is what appears to be Thresh's face. Can't say there's much surprise there, though curious why him of all the possible shadow isles champs. Also, not sure if it's just to highlight one of his tentacle-like-hair-things but On his forehead there's a spiral shape that has a strong resemblance to Kindred's marking. If it's just a way to make the hair-shape stand out, then lol. If it actually happens to be an insignia like Kindred's, then there might be a special meaning to it and its purpose.
And on another note, any special meaning to the face/portrait on the upper part? I can imagine easily leaving these areas blank or just adorn them with decor like the vines and the spider web (to show that Vilemaw is there) and such, so why the faces? inb4 people saying that's obviously Sena (or was it Senna) up there, but I think the TT map has a few more things hidden in there that tie into some lore. Definitely want to hear more about the Shadow Isles as it is one of the stronger antagonist forces in the game, where even Kindred and Illaoi with their seemingly godly tier powers dislike them as their quotes show.