Would help if you posted your full roster. If I am reading this right I would say Coldheart. Easy for you to fully book and a great all around champion.... but once again, I would need to see your roster. 

Getting a 6* promoted is a significant push mainly because you are doing two things very incorrectly:

1) Don't waste time in Nightmare campaign. It's a complete waste of resources until you reach Stage 12, and even there, it's only marginally better than Brutal in terms of XP per energy, and it's worse than Brutal for other resources.

2) You are almost certainly not farming food properly, if you have only Ruel and Laz as 60s. You need an efficient campaign farmer, and for the vast majority of people - yourself included - your starter champ is the best option for this.

Of course, as Shibb mentioned, you should post your full roster, as there's a very good chance there are better chocies, but in isolation, I'd say you should get Elhain to 60 next, so that you can use her as your campaign farmer.

No worries, will post roster tonight.

2) You are almost certainly not farming food properly, if you have only Ruel and Laz as 60s.

The short answer to that is I had a stupid lucky pull to get Lazarius, used some spending $$$ to accelerate longterm resources, but am only at week 3 + a couple days in the account.  So, pretty early in this.  I am settling into f2p mode, however, and farming pretty relentlessly.  I do agree farming is the way forward, so no worries on your critique! 😁

The problem for you with Mythical champions especially, but also Lego ones, is that unless you are spending a *boatload* of cash, you'll almost certainly not have any tomes for them. And without tomes, their abilities have longer cooldowns, and for the Lego champs, they also have a reduced chance of landing debuffs, which makes them *significantly* less useful.

Priority 1 is getting a campaign farmer that can clear Brutal 12-3 or 12-6 in under 15 seconds, so that you can just power through food farming. Elhain can do that, since she has two AoE moves. Neither Ruel nor Laz can pull that off, even if they may be stronger champs. While, technically speaking, Laz does have two AoE moves, he needs to shift forms to do that, which, combined with his passive putting buffs on people, makes everything slower. Still - he's probably your best bet for now, and should be able to clear in under 30 seconds, hopefully.

Side question on resource allocation.  I've assembled all the Relickeeper fusion pieces for eventual use in Arbiter missions.  I've been using my training grounds (all 5 slots opened to lvl 2) to grow them on the side so I can faster train up other champions like Coldheart and Apothecary in Campaign missions.

I've been expanding Arena rosters as well.  I'm well short of competing in Gold I, but winning about 12 Silver IV matches per night, and lower-powered Tagteam Arena matches as ways to work around energy limits until I get Adelyn's chase done (not gonna miss out on her five soul pieces!). I've also worked into the Faction Wars just night.  Lizardmen (Lazarius solo) and Banner Lords made it to the first boss fight each to get me two books).  Sacred Order is ready and Dark Elves will be ready, soon.

Should I stop the side-hustles for now and focus on solely food running?

That depends entirely on how much you value efficiency over just general enjoyment of the game.

The short answer is that literally everything you do aside from leveling food and completing daily/weekly/monthly quests, right now, is simply a waste of energy. However, given you're new, I expect you also just want to play the game, and not just do things with absolute perfection.

So, what you really want to do is, as much as possible, avoid wasting *valuable* resources. Energy is cheap, and if you decide you feel like randomly running some dungeon just to see how it goes, or experiment with different teams, go ahead.

On the opposite end of the spectrum, shards and tomes are *not* cheap. You should ideally not use a single ancient/void/sacred/primal shard, period. You should save those for when you are ready to do fusions. Similarly, you should *definitely* not use legendary on champs unless you are *sure* they will be useful for you - and Ruel does not fit that boat. You should also not use tomes on anyone of a lower rarity than the tome - EG don't use a mythical tome on a legendary champ. You can, however, feel free to use your mythical tomes on Laz, as he's a very good champ.

The other big mistake people make is wasting resources on champs in general. This goes for leveling them in the training pit, as well as just generally doing things like ascending random champs. Try to resist that temptation. There's a *very* long list of useless champs in this game, and Faction Wars is a great way to fall into that trap. If you must use them, then try not to level them beyond 5*.

Hmm, good points.  I can see your point on Ruel, as he and Cillian both are probably not endgame Arena slots.  That said, gotta work with the team I have for now!

i

And, voila!  This is what I have to work with, currently.

Okay, so good news - you haven't made many big mistakes, from what I can tell. Really the only one I would definitely not have done was level Tallia to 50 and ascend her. She's quite a sub-par epic champ. But, what's done is done. Aside from that, you should probably stop leveling epic champs to 40 - I assume you're doing this using the Pit, but doing so essentially throws away resources, as you're not going to get food leveled instead.

In terms of who you have that is worth investing in - not necessarily now, but eventually -

• Husk - great AoE nuker, and has a nice provoke to boot. Definitely will be useful for Spider and Hydra.
• Torturehelm (often referred to as Smiles) - probably won't end up being used, but he does show up on some niche CB teams.
• Uugo - top-tier debuffer, and brings very useful healing and even a token revive to boot
• Oathbound - *probably* won't see use, but he does bring an AoE ATK Down on his A2, which is absolutely something you'll need in CB
• Vergis - lots of areas where he can be useful. There are even some CB teams built around him.
• Fenax - personally I don't love him, but other people swear by him. If nothing else, the block revive has value in a few places.
• Deacon Armstrong - top-tier buffer, and is essential on some CB teams. PS - use your Guardian Hall to make your second deacon a guardian, to boost that faction. 
• Sandlashed Survivor - the A1 provoke has value in Hydra, and the A2 buff extender is absolutely essential on some CB teams
• Apothecary - may not end up being used, but for now he is your best SPD Up champ
• Coldheart - top-tier Max HP Nuker. Definitely will see use on Spider and FK.

For now, I think I would probably build the following Dragon team:

• Apoth - SPD up and healing. Bring him to 50 for sure, and you may be able to just leave him there.
• Uugo - Debuffing, healing, and backup revive. Definitely bring her to 60.
• Laz - just all-around amazing, even unbooked. He'll be your wave-clearer. Make sure to set his swap-form + AoE nuke as disabled on the first wave, so that he doesn't waste them both on the same wave.
• Coldheart - Boss killer. Make sure to disable the A3 on the second wave, so she saves it for the boss.
• Husk - for now he's your best AoE CC, even though he's really not good at that job. Still, it's unlikely you have anyone better for that spot.

Well, Tallia was in the first wave of champions I got in the first few days who survived culling and I already know her days outside of Faction Wars are limited.  But your point is solid.

I appreciate the time you took to reply.  I'm still getting the hang of working in the tier lists to analyze various team usefulness.  This gives me good stuff to learn from.

I'm guessing your advice holds to Elhain as 6* next?

Yeah. None of your other champs make for good campaign farmers unbooked - and rare tomes are quite easy to come by.