Vintrict
A little more clarification on the floor. It is, in fact, a marble-like material. I say marble-like because the floor is meant to be destroyed if a large amount of force that super humans are capable of throwing around is thrown into it. I suppose I should have added more detail on this since I wasn't thinking about everyone's needs. It makes up for the "no immediate soil" that usually softens landings. Underneath is soil and natural earth, and some stone, so earth users aren't completely gimped. You'll just have to put some work into summoning it through the floor, which isn't really hard with a couple of posts.
As for KB, this is actually pretty difficult to rule. Your character's weakness shouldn't be a weakness that is suddenly removed just because it will be a weakness that kills you instantly if you go into sunlight. If anything, I'm throwing a 50/50 ruling on this. The sun is shining at an angle during a different time for your fight, meaning that shadow covers the east half of the ring, but doesn't cover the west. Plus, if anything, I expect KB to be intelligent and just walk into the fight with a cloak on. That way, he has to realistically protect himself from the sun and his opponent, because I expect people to deal with their flaws to make a believable and more interesting character. I can't just give you a roof cover like that. A vampire entering a tournament is common. A vampire entering the tournament weak to sunlight is not. Therefore, they should compensate for this. Tournaments are often day events.
As for KB, this is actually pretty difficult to rule. Your character's weakness shouldn't be a weakness that is suddenly removed just because it will be a weakness that kills you instantly if you go into sunlight. If anything, I'm throwing a 50/50 ruling on this. The sun is shining at an angle during a different time for your fight, meaning that shadow covers the east half of the ring, but doesn't cover the west. Plus, if anything, I expect KB to be intelligent and just walk into the fight with a cloak on. That way, he has to realistically protect himself from the sun and his opponent, because I expect people to deal with their flaws to make a believable and more interesting character. I can't just give you a roof cover like that. A vampire entering a tournament is common. A vampire entering the tournament weak to sunlight is not. Therefore, they should compensate for this. Tournaments are often day events.
I like marble, its beautiful, symbolic, and squishy compared with stone. kind of like the "brass" of the rock family.
I've heard of a lot of different explanations for vampires vs. sun. There's the magical light = holy damage, which can be blocked by something like a cloak, then there's the "needs thick walls in pitch black room" ultra violet radiation light, that even if you are in the shade of a tree, you take some damage.