Basically a mode/option where your vision would be limited to your tori's vision. You would still be able to see the environment even if you're not facing it however your opponent will only be visible if he's/she's in your tori's line of sight.

The way it would work is that the "Vision System" or whatever would check to see if your tori can see your opponent:

#1 - At the start of the turn (pick one then go to #2):

• If your tori can see your opponent (any part of your opponent's tori) at the beginning of the turn, opponent's tori and ghost can be seen.
  
  
• If your tori cannot see your opponent at the beginning of the turn, opponent's tori and ghost cannot be seen.
  

#2 - When the turn ends, and both tori's begin to move (pick one and then go to #1):

• If your tori can see your opponent when both tori's start to move then your opponent's movements will be seen until the start of the next turn.
  
  
• If your tori cannot see your opponent when both tori's start to move then your opponent's movements will not be seen until he is in view.
  • If your opponent jumps into your tori's line of sight during this time, then a transparent version of your opponent will be seen for as long as he/she is in your sight.
  
  

In case of dismemberment's:

• If an opponent's joint/limb is dismembered from his main body, putting that body part in the view of your tori will not make your opponent's tori visible. That applies to the head as well.

Spectators will be able to see both tori's. If a tori cannot see their opponent, maybe there could be a little symbol by their name to indicate that they are 'blind.'

The idea behind this suggestion is to give players an incentive to play realistically by making sure your head is up at all times. It would definitely be hard to grasp for most players who don't spar regularly (or at all: me) but it would definitely be a more interesting take on fighting mods.

Let me know what you think.

And neck rotates sideways?

This is a very good idea. I hope to see more of this!

Press 3, thank me later.

Nope, not in Toribash. But I think your chest can rotate sideways unless I'm completely mistaken. Correct me if I'm wrong.