It'd help to see your full roster, but I would probably go with either Bellower or Kael.
On the one side, Bellower will help you farm campaign more effectively, and can be used quite a bit into endgame as a dedicated stunner.
On the other side, Kael will help you with clan boss early on, which might let you advance faster - however, will probably be replaced by Frozen Banshee if you get any ally-attack or counter-attack champs.
tl;dr I'd probably go with Bellower.
If after 1 month of playing you are working on your first 5* champion, you surely take your time and hopefully enjoy the game.
You should take Kael in my opinion. krama is right that Bellower can help you out with a stun set but I have the feeling that you are not getting one soon.
Concentrate on Kael, bring him to up to a level and gear state in which he can solo farm 12-3 brutal and the follwing leveling will become much easier.
Thank you all. I appreciate your advice. I've been focusing getting Aleksandr to asended to level five along with Urogrim. I did that and now want to focus my other epic, Jizoh and one of the rare's I asked about. I should have given that information from the beginig. Sorry.
Can you post your roster?
Any of those three champions you posted are going to be a better option than Jizoh.
Don't spend any resources on Jizoh. Also, don't spread yourself too thin. You ideally want to focus on getting a single champion to 6 star instead of having multiple champions at 5 star. I would take Kael to 6 star if I were you. He can work in all formats, including campaign, arena, dungeons (especially dragon) and clan boss
Once you have Kael at 6 star then figure out which champion to increase next