The Reason Zenos.

[Mahoukenshi]

I did read quite a few post about Zenos before I reached and completed SB, but tried to not let it influence my opinon too much. However, eh... He turned from a boring kill or "hunt"-obsessed doll to a mentally-derranged stalker with yandere tendencies who got even more power (as in abilities) shoved up his rectum with no effort. Not speaking of the other potential stalker Ascian in his body... I've seen better serial murders in the various crime documentations out on tv. To be fair, it didn't help much that SB was very in-your-face in painting 99% of the Garlean villains as typically evil. The rest like Frodola and Tsuyu, at least, had background revelations, which may have been as well kinda cliché with horrid past, but made them overall better in the great picture for me. Maybe I'm just having double-standards in prefering certain trope confirmations over others, though. Seein that I liked what they did with Frodola post-SB and the "twist" with Tsuyu.

I don't even think the problem is or was that these rival-type characters (villain or not) have already started out overpowered, but can't put the "why" in words.