Grand Unifying Guesses/Unkillable

These characters cannot be killed by Saint of Killers, but would be incapacitated for quite a while.

 * Captain Jack Harkness
 * Captain Scarlet and Agent Black
 * Marvin The Paranoid Android
 * Mr. Immortal
 * Vancuria (Nai and Mea)
 * The Saint of Killers' successor/alternate universe counterpart/mild-mannered secret identity, however, only chooses not to kill them permanently, for undisclosed reasons.
 * Ash Ketchum (and Team Rocket)
 * Starscream (He could technically be killed, but as always his Spark would endure and reincarnate).
 * Suzaku Kururugi
 * Deadpool

As a side note, the characters in the guess directly above completly immune to The Piemaker's touch, As are these others below.

 * The Doctor
 * Jack Bauer
 * Kamina