For eternity:
* Evermore: This implies a timeless and unending duration.
* Eternally: A more formal and grand way to express forever.
* Perpetually: Similar to eternally, but often used for something that happens continuously.
* Forevermore: A blend of "forever" and "evermore" for extra emphasis.
For consistent repetition:
* Continually: Suggests something happening without interruption.
* Incessantly: Emphasizes the relentless nature of the action.
* Unceasingly: Similar to incessantly, implying no pause or break.
* Endlessly: Stresses the limitless nature of the action.
For unwavering loyalty:
* Everlasting: Implies a bond that will never break.
* Indelible: Suggests something that is deeply ingrained and permanent.
* Immutable: Indicates something that is unchangeable and fixed.
Other options:
* Ever: Simple and direct, emphasizing a constant presence.
* Abiding: Suggests something that remains steadfast.
* Unfailingly: Stresses the reliability of something.
The best word depends on the context and the specific emotion you want to evoke.