'The Final Dimension' subtitle ...
... made me initially think that this movie was going to involve parallel universes in some way, shape, or form - that Kane was going to be an Immortal from another reality who had somehow crossed over into the mainstream timeline, allowing Connor to battle another Immortal without contradicting the ending of the original film.
Instead Kane and his cronies were just Immortals that got trapped, missed the Gathering, and were inexplicably forgotten about. You'd think the Immortals in the first film would have had some sort of instinct or feeling that they weren't the last ones left on Earth if that were the case.
Life is like a box of chocolates. A cheap, thoughtless, perfunctory gift that nobody ever asks for.