immortal
monstermanual page 19
immortal
Arguments
Takes no arguments.
What it does
The monster is immortal on its home plane. This command should not be used for beings with Other Planar Immortality.
— modding manual, page 19 (as a monster command)
From the base game data
monster data
immortal
Interacts with
“Useful values are 2^4 for undead, 2^20 for immortal and 2^26 for ethereal.”
— resrestrict's description (manual, page 34)