Counter to Undying Rage?

basically all CC / kiting tools to get away from him.

His wife is also a good choice to smack him upside down ..

or shoot him ... upside down ... but that doesn't make English sense ..

Ignite right before it wears off will kill trynd unless he has a finished botrk and something to lifesteal on.

Alternatively just burst him and disengage after he ults then fight him while it's down since it's a pretty long cooldown. He's a melee champion that builds zero defensive items so it's pretty easy to force his ult.

There's CC, but of course, as stubborn as any other players do, you dont want to hear that.

its not OP and yes there are many

Root/slow counter it, entirely. If u get him low - leave or just hang back. It would be a lot easier if u said who (champion wise) you play. Once you get him to panic/ult you won stop trading, even if he has hp left.Burst/hard cc ifu dont want it to ever actually get used, any stun with burst where the stun hits around 50% hp means he's not gonna be able to ult or has to ult at rly high hp and then you win. Srsly tho which champs do you play? A or are great item counter whereas and so on are great champs to deal with him with or without items. Pro tip getting boots/boots with furor is easy mode ;3

Morellonomicon works wonders against him, along with ignite. Also, picking someone that can out sustain him through his invulnerability like a Vlad, Trundle, or Olaf also helps. If he ults in the middle of your team, spread out just enough that he can't hit you all with his slow/AD shred or his slash and try you best to CC him if he goes after your carries.

after a few seconds and run away.