My second was Stag Knight.  I like Rector Drath's skills quite a bit.  Very nice support champ.

You should include what you want to use it for (generalist, clan boss, arena, etc.). 

I'm only level 51 for what it is worth.  I don't have Rector Drath.  I do have Stag and Painkeeper and l would upgrade Stag over PK.

I'd definitely go with Rector Drath. Insane support kit and can be your atk down champ for CB as well. 

After Rector, I'd go for Stag Knight and maybe Achak. 

Good luck!

Rector  Drath

Stag  Knight

Those  are  the  main  two,  its  close  between  them.  Personally  Id  take  Stag,  but  its  your  choice.

Later:

Alure

Rock  Breaker

Pain  Keeper

Achak  the  Wendarin

Alure is my favorite but I agree with the others. A good support champ is always needed throught the whole 

support champ for sure one who can heal etc will be vital to help you out 

Alure was a game changer for me, and is very useful even at 50

I'd do this first, and then think about who to get to 60

Rector  Drath and Stag  Knight 2  are the main two, it's close between them.  Personally  Id takes Stag,  butat the final it's your choice.

Later this two you can go with: Alure, Rock  Breaker, Pain  Keeper, and Achak  the  Wendarin.

Hope you like Ometv and  Chatiw 

Love from Canada.