A while ago I posted https://www.legendsofleague.gg/league/post/40/ivern%2520blog/, an interesting ivern one trick blog at https://www.ivern.io/. One of its posts on why he dislikes rengar ivern I thought was silly. But last month he commented explaining a bit more. One big thing is ivern enables bruisers with his E, but rengar normally is an assassin, so ivern rengar requires a change in playstyle from the rengar. So it's not the best synergy. I don't think I realized that a year ago, but since then all the good rengars I've seen have been full lethality one shot, going for picks rather than jumping into a teamfight where they'd instantly get cced and die. So yeah mb sounds like he was right:

"With conventional bruiser/fighter champions like Darius, Sylas, or J4, Ivern is able to make them better at doing their job, making for an easy and consistent synergy. On the other hand, Ivern paired with Rengar gives him new jobs to fulfill."

also lol I called garbo early season chall but he finished the season chall, so mb congrats xd