Fenris? OP? HAH!
In my experience, the only time that Fenris is a problem is if my teammates die left and right in early game - meaning,
if he's fed a lot. In my experience, Fenris has a heck of a time getting gold from anything except hero kills, because he lacks real AoE. If he doesn't kill anyone in early game, he won't be able to overpower you later.
Likewise, if you and your teammates do your job instead of trying to play "EotA Hero Arena," he will have to spend his money on Mercenaries, repairs, rebuilding obelisks, or any number of other things BESIDES permanently increasing his own power. Hero killers don't inherently win hero conflicts - they're just slightly better at them when built for it. Stop the build.
Feeders make any hero a problem. Fenris more so than some, but less so than others (*cough* Infiltrator or Swashy).
Furthermore, EotA is not a game about fighting fair. Don't let him engage you in a vacuum. Move in pairs, or at least have someone in a nearby lane who can come to help before you die. Carry consumables. Stick near your spawnies. If you can get Fenris surrounded by spawnies (nets are GREAT for this), he'll have to use his dream run to get out, and if he tries to keep persueing you, then he won't have it to escape later when you nuke him.
If you're routinely at low enough health that Fenris can kill you before you or your teammates can react, you have bigger things to worry about. Like infiltrators.
