Captain Tool And The Last Unicorn

So, I was going to draw a Picture of Onos T'oolan, one of my favorite Characters from the Malazan Book of the Fallen (the scene were he is making the arrowheads).

Then all this started with my Question in the Chat over at malazanempire.com, what is the Color of his Flint Sword, because i couldn't find the description.

At some point i said that i will just make it look like a rainbow, and then somebody said something about Captain Tool and a reanimated Unicorn. That Idea just got stuck in my head, so i had to draw this instead.