I've had my unblockable blocked by the gladiator which really surprised me. I'm not sure how this is possible.
Also, it doesn't make sense to not be able to block the skewer from the gladiator. I can see the direction to block it. Any bleed attack from another character can be blocked. I think that all bleed attacks should be taken away and replaced with the sharpen blade feat. If it's not a feat then every character should be able to bleed.