PC?! Dear gods no... I wouldn't let a player run Deadpool. That's Prime Runner material right there. My players would spout off to dragons if they knew they could eventually regenerate most forms of damage.
SR4 regeneration doesnt' work on Magical attacks (Magical creatures, Spells, Killing hands etc)
Dragons are dual-natured creatures with Natural weapons (which count as magical attacks) and you still die from magical overflow if you're too far gone to regenerate to '
Alive but in a coma' in your first turn
ie, if you have 4 body (a 10-box Physical damage track), already have 8P damage, and take
another 8P you're at 16 damage (which is +6 Physical Overflow).
Note: Base dragon damage per claw-swipe is about 8P
)
With 4 body, you can still be alive at 14 damage (+4 overflow).
If your Regeneration test (Magic plus body) only gets 1 success (taking you from 16 damage to 15), then unfortunately you are dead, and stop regenerating.
So the regeneration power in SR4 isn't as good as being a Highlander or Deadpool, and as thus you should not be spouting off to dragons