Auto-translated
The first thing that comes to mind is a pyramid with a throne on top. This evokes associations with grandeur, like a hero at the peak, and there's no room for anyone else. However, such a structure doesn't look fast; it seems like it should slowly float above the ground.
A stone with a flat top and a narrow base should fly faster, with sparks flying around it, but crystals would be better. The advantage of this design is that there can be more details on the stone. For example, there could be an anvil in front of the hero, which he will strike with his staff during casting, or a pentagram, or a book on a pedestal, and something else on the sides, maybe magical crystals or runic columns.
I don't know what to do with the flag. Maybe it could be a heraldic shield above the throne, with the Chaos Star on the main shield and symbols of the colors on the side shields.