Until the release of Battlecast Vel'Koz, I would have been content to believe that the silhouette seen in Creator Viktor's recall animation belongs to Battlecast Anivia (a skin alluded to in Battlecast Prime Cho'Gath's blueprint, along with many of the other members of the skins series), or even Aatrox (with his sword hiding his legs). However, the silhouette seen in Battlecast Vel'Koz is — while undoubtably of the same creature — flying with vertical wings (even with the skin were legendary, that's too stark a difference to Anivia's standard silhouette).
I initially believed this creature to be Kog'Maw's dad based on the speculation that his dad will be the moth/wasp/butterfly to Kog'Maw's larva-like appearance (it's definitely one way to have a family resemblance without Daddy'Maw just being a big Kog) - so I set to drawing sketches. However, the shape of the wings just doesn't support a bad-ass looking insect (something most of the void creatures have in common)!
So I started over on both accounts.
Kog'Maw's dad took a new direction, combining features of Kog'Maw and many winged insects (including one based on the winged silhouette from Battlecast Prime Cho'Gath's artwork). I'm currently drafting a kit for him with a few guys on the League Wiki - his huge maw and gut will be put to good use. His ultimate's currently reading along the lines of "Reflux - ACTIVE: Muzen'Khan swallows the target enemy and can activate Reflux again to spit them at the target location, damaging and knocking up all enemies in an impact area"
, and I can just imagine the swollen stomach!
And a completely new creature for the unidentified silhouette! I'm currently imagining that it's Kassadin's daughter, due to the pseudo-humanoid/fleshy appearance (something that would contrast to the other voidborn if the creature was native to the void). I've drawn the non-Battlecast version, so the silhouette isn't an exact match. After my first doodle, I was told it's head looked similar to Faceless Void (believe it or not, I don't play or know of most of the Dota heroes) - but, after Googling him, I embraced the similarity! I honestly don't know what I'd call it... some sort of manta ray mermaid hybrid.
I'd love to hear your thoughts on the unidentified silhouette, Kog'Maw's dad, Kassadin's daughter, and the two creatures I've created which may or may not be Kog'Maw's dad and Kassadin's daughter (although the latest version looks more masculine than feminine).