First thing's first - you shouldn't really consider this game a "role"-based game, not in the traditional sense at least. It's possible that champ do end up fitting into those "roles", but more often than not, they can't be pigeonholed so easily.

As an example, would you consider Sinesha a healer, since she has a strong A2 and A3 heal? Would you consider her a lockdown champ, since her A2 puts skills on cooldown? A damager, since her A1 can hit twice and can hit quite hard? She doesn't really fit into any of those roles specifically.

To your specific question, it largely depends on where you are going to be using Kael. If you're using him for arena, you build him purely for his A2. You ignore accuracy completely, and focus entirely on ATK/CR/CD. If you're using him for CB, on the other hand, you go the exact opposite route - you want to focus on ACC/DEF/HP for CB. Dungeons are a bit of a combination of the two.

Same goes for Tayrel. His utility is largely centered around his debuffs. If you're using him for CB, you usually want him to run ACC/DEF/HP. For dungeons on the other hand, since the need to land debuffs is significantly diminished, you'd usually want to run him with higher speed and DEF, sacrificing some of that accuracy and HP that you need in CB.

Apoth is simple. You just want him to be as fast as possible. The other stats are largely irrelevant.

she fits into all i would consider her a support/healer cuz she heals and locks down champ skills also i use these champs in just about everything but i mainly focus on cb so their stats fit accordingly except i disagree on what u said for kael for cb. i keep as much offense and accuracy as i can get on him while keeping just enough hp and deff so he doesnt die quickly. hes one of my last champions standing because instead of putting alot of def on him he has high attack and life steal gear. other than the difference in opinion over kael cb stats i completely agree with you. thank you for your opinion

You're certainly within your rights to disagree with me, but I hope you would go and do some research - I am not incorrect in my opinion. And I've got waaaay more experience playing this game than you do.

The reason why you want to focus on ACC/HP/DEF on Kael for CB, is because his role on CB is to put poisons on the boss. CB is an endurance fight, not a rush to do as much damage as possible quickly. The longer the fight goes on, the more damage those poisons do.

And, especially importantly - the poisons will 100% outdo ANY damage your champs can do on their own, especially right now. Putting ATK/CR/CD on him is 100% a waste of time. You can get some tangentially from substats, sure, but you absolutely should NOT be using ATK%, CR%, or CD% gloves, chest, or boots.

Most likely is, you'll run speed boots in order to get him speed tuned properly, HP% or DEF% gloves, and either HP%/DEF% chest or ACC chest, depending on whether you can get enough accuracy from substats and set bonuses. For accessories, you'd run him with a DEF or HP ring, a CDMG amulet with ACC substats, and either an ACC banner or a DEF/HP banner, hopefully with SPD substats.

This goes for *all* your CB champs. Your objective on CB champs is to get them properly speed tuned so your turn orders execute correctly, and then to get them in as tanky gear as possible in order to meet the minimum  defensive breakpoints. Once you cross that boundary, sure, you can start looking at offensive stats, but I very much doubt you're there yet.

I just put some links in another thread, but I see this applies directly here too... so if you are interested, here are some videos where HH builds some solid teams, and walks through his choices on champs and team roles, what gear he is using, etc.... it is a great intro to champ building and gearing and team composition, and you can pause and look at builds in detail and whatnot. If not interested, that's fine, but I share this often with my cluster. :)

Beating and farming Dungeon 20s with One Team To Beat Them All Wonderful video on how to build a good team that can farm anything. Answer things like What do I need to build an effective team? What skills and gear are important? What are the strategies and methods to beat each dungeon? https://youtu.be/ziwDFgAPoz8  

Second video on One Team To Beat Them All This time with totally free champions, no real RNG even (login, etc..). Learn more about what skills and builds are important to beat all the level 20 dungeons, as well as more strategies for beating each dungeon. https://youtu.be/iWpsP4K164Q 

Building a quality CB team in the first 45 Taking a step back from NM and UNM to show you how to build a Hard/Brutal CB team in your first 45 days playing the game. https://youtu.be/PKc8SHqKkK8