This is my theory on how the story may end.

Rover may be the final boss and we will defeat him and all the threnodians will be struck in him forever.

This is just my guess but maybe rovers plan is to absorb all the threnodians and end himself so they will be struck in him. As he is the only resonator capable of such feat(my opinion).maybe he reset his memory so he can roam the solaris and make friends and trustworthy allies who will in the end give the finishing blow. Maybe he made sentinels so they can protect the people and find a person strong enough to inherit his powers. Well he alone is strong but imagine him with all the threnodians powers who will defeat him and then threnodians will make sure he won't end himself and no one can defeat him and he is the arbiter of the sentinels so they won't attack him maybe he gave the sentinels info that they can have their own resonator and as they are not like the sentinels and will fight him.

U know maybe there will be a scenario where he will be the final boss and all the sentinels resonator and our friends fight him and he will try his best to hold back his powers like kim dokja when he became the demon lord ( omniscient Reader's Viewpoint)

Note: there maybe grammatical mistakes ignore them.)