Never-ending and Prelusive

Never-ending adjective - Uninterrupted in time and indefinitely long continuing.

Prelusive and never-ending are semantically related. In some cases you can use "Prelusive" instead an adjective phrase "Never-ending".

Prelusive adjective - Coming before the main part or item usually to introduce or prepare for what follows.

Never-ending and prelusive are semantically related. Sometimes you can use "Never-ending" instead an adjective "Prelusive".