Champions that will never defeat their rival

What are some champions you think that could realistically never defeat their rival?

While most rivals are fairly evenly matched like , I noticed a few champions have rivals they are unlikely to ever defeat.

The ones I can think of at the top of my head are: and

Lucian I think is a prime example and in a massively worst spot than Irelia in his struggle. While Irelia failed to kill Swain when he was a normal human and now he's an unbeatable demon bird thing she at least has Ionia backing her and Ionia was strong enough to drive Noxus away so there's hope.

As for Lucian defeating Thresh along with the Shadow Isles this is an impossible task, we already saw his showdown with Thresh and Lucian couldn't even scratch him and was about to be consumed, and in a last ditch effort he slipped a special silver awl he kept in a locket into Thresh's wrist which caused the souls inside of him to rebel and fight back giving Lucian an opening to actually hurt him enough to force him to retreat back into the mist.

Problem is after this encounter it's unlikely Lucian's trick would work again as Thresh will remember, and continue to get stronger and stronger. Then there is the rest of the Black Mist he has to deal with as well along with Thresh like Mordekaiser and Hecarim, and likely the only way to truly defeat him he's going to have to go to his home in the Shadow Isles as Thresh simply returns there when he's either done hunting or gets hurt.

So likely the only way Lucian can defeat Thresh and free Senna is to destroy him in the Shadow Isles so he has nowhere to run, unfortunately this is where Thresh is at his strongest surrounded by undead who would gladly tear Lucian limb from limb making this a suicidal move.

And every day Thresh is active he's growing stronger from the countless souls he's capturing to empower himself, while Lucian even though at the moment a fairly young man in his prime will eventually get weaker as he ages/sustains injuries. So basically 6 items Lucian vs 6 hours farm Thresh...

Lucian also is a bit of a loner so he gets no help, and from my understanding he is the only person in Runeterra actually actively fighting against the Shadow Isles. Sure when a harrowing happens people try to either run away or defend themselves but no one really has the tools, knowledge, or care to fight against the Shadow Isles, and the undead grow stronger every day.

To make matters worse not only does he not have any help at all he's enemies with essentially every Shadow Isles undead and more importantly enemies with and along with who are all far more powerful than he is, especially Mordekaiser, Thresh is nothing compared to him, and Lucian can't 1v1 Thresh.

The only way he's going to win that matchup is if he gets some powerful allies. Unfortunately not alot of champions seem to care at all about the Shadow Isles or being even strong enough to challenge beings like . For instance doesn't seem too busy and is well equipped to deal with these guys considering she can lift mountains and her magic blots out other magic, but fat chance going all the way to Ionia and convincing her to fight some bad guys in the Shadow Isles she doesn't care about. There is who will probably be interested in defeating , but I'm not sure a team up is possible.