Ok, been looking at this as it is one of the two kinds of characters I needed the most for an upcoming RP (Immortal being the other one). Here is what I've put together for the 'Musts' section of the Template.
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Physical Immunity [-8] (page YS:186): Death can not touch you. Drowning, starvation, gun-shots, stabbing, bombs, fire, etc, the cause doesn't matter, you do not die and - if your brain is in a shape to process input - you feel every bit of it. No resistance to damage is gained, but regardless of what wounds are inflicted upon you, death will not come... no matter how much you may wish it would.
The Stacked Catch [+6] (page YS:187): This catch allows everything except for the specific act of death to bypass the Physical Immunity power. When one of the Undying is Taken Out, death will not result from any action taken as part of the victory conditions. Similarly, nothing - except perhaps plot device level effects - can cause the character to be made temporarily or permanently dead. Discovering the conditions of this catch would not be difficult, though some might wrongly assume that death can be caused by some specific means.
Must also take one of: <i>Inhuman Recovery [–2]</i> (page YS:185), <i>Supernatural Recovery [-4]</i> (page YS:186), or <i>Mythic Recovery [-6]</i> (page YS:186).
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From what I read in this thread the numbers are good, but I'm hoping I worded everything correctly in the catch to justify the +6 refund.