Moshiach will not die

Moshiach will have length of days, without end. (Kisvei HaRamban, I:325)

Moshiach will never die, rather he will live forever. (Birkas Shmuel, Bereishis 2:16)

Moshiach will not taste, the taste of death. (Otzar Midrashim 2:10)