The Black Kodiak was a demon spirit taking on an image of a horse to roam around freely. However, everyone in the stables only saw him as a special one that was not kept in there. During festivities like this, he was not supposed to take part; neither did he lead the procession back at the first wedding. Moreover, he was still healing his body from the attack of the glass spirits. He should be sleeping and resting in the shadows.
However, he didn't feel quite right skipping this ceremony. Not only did the people knew that the archduke's horse was the sleek black one, but he was also interested in how the other horses saw such procession and cumbersome show. The horses this year were not even born when the first wedding was held.