Usually not comparable; comparative and superlative forms are rare and non-standard
Translations
The legend of the immortal hero has been passed down for generations.
Легенда о бессмертном герое передавалась из поколения в поколение.
Definitions
Living forever; never dying or decaying. The vampire was considered immortal, as it had lived for centuries without aging.
Enduring and lasting forever in memory or fame. The poet's immortal words continue to inspire generations.