Humans

 If a player starts with a orc team as their first team, the natural progression is to continue on to the human team and take advantage of the legendary event character Solius. This also leads to a second unlocked legendary: Mor'Doom. Even outside of unlocking Mor'Doom, the human team is a fantastic choice for your second team to level up.

Bench warmers

Lets start with who you don't want to use.

Robin Bad - honestly his damage output just isn't up to par with the rest of the team. I have heard people use him in raids for his turn reduction, but there are better choices for this IMO. I haven't bothered leveling him yet.

Dorian- Dorian needs a major buff to be a viable hero. He is often thought to be the worst defender in the game. On the human team alone he just gets outclassed by Little Batty, a better option in his role of tank.

Selena- the only reason to use her is you haven't unlocked Solius yet. She has some weird ability that randomly steals taunt and puts it on a character you don't want attacked. To be fair it has potential, but the randomness of it is just crappy. She does have some viable heals if you get stuck using her.

Snorri- Yes there is some synergy with Freezard. You could use him as an alternate if you can't gather up enough shards for one of the ones listed below, but I don't see room on the team for him.

Core Team

Little Batty

Little Batty is simply one of the best tanks in the game. She taunts, she slows opponents down, she has a chance to blind, and she is pretty difficult to take out. You really cannot ask for more in a tank.

Runes: You want to make your tanks as hard to kill as possible. For this reason, I strongly suggest armor set runes. Next priority is to raise potency, specifically us a potency primary in your top left rune. Your top right is the perfect spot for a speed primary armor set rune. Lastly, an armor primary on the bottom.

Artifact: You want an artifact with potency and armor. If you could find one that increase survival in any way as a secondary effect that is icing on your cake. 

Freezard

Freezard is your primary damage dealer and has an array of great debuffs while throwing out said damage. Slowing down a key opposing hero can often seal victory. 

Runes: Speed is your friend, as such 4 speed set and the top right speed primary are key. This is one character I would take the time to find speed stats as secondary stats as well. Next you can chose between potency and crit for the other two. I like potency. Also utilize potency as your primary stat in the top left.

Artifacts: For your offense stat, anything works. If you want more potency, find an artifact that increases potency. For defense, I'd go with lifesteal, armor, or maybe tenacity. Almost any artifact ability that seems cool would likely take priority over optimal stats.

Cruelle

Cruelle comes in late game and is kind of a pain in the butt to farm, but she is worth it. She has a unique ability to make copies of opposing characters, which is really neat. However, I find her most useful ability is to turn tanks with taunt on them invisible. When there are three mages on the team (which could be clones) she turns them invisible as well. Invisible is a huge buff against counter attacks and are great at making the mages harder to kill. Overall highly versatile character.

Runes: While her abilities are unique, you still want to start with speed runes. Next you have a choice between potency and crit. Potency lets you land the invisibility on tanks more often (I think), I'd lean towards that.

Artifacts: Again, a cool secondary effect would have me gravitating towards using that artifact over one with perfect stats. There are some that take advantage of being invisible that would be great here. Also she has her key artifacts that have interesting effects like possibility of removing buffs from targets. Aside from a cool secondary, raising damage would be my preferred attack stat and health or armor for defensive.

Eric ShieldBreaker

Eric was a sleeper for me. Meaning he seemed pretty "meh" to begin with. Once powered up he became one of my favorites on the team. He packs a powerful punch and increases damage to pack an even more powerful punch next time. His debuff block is a huge boon against all the debuffing teams you will face.

Runes: Damage is key. I went with 4 damage runes and 2 crit runes. Of course you want speed in the top right and any secondaries, but more damage in the top left, bottom primaries, and any other choices you find. 

Artifacts: Damage increase is my primary focus here as well. Specifically a % damage increase as he should have over 3,000 physical damage which makes % bonus better than the flat bonus. Secondary effects that boost damage in any way are bonus here. When something hits like a truck, find ways to focus on that.

Solius

Solius is the key that takes this team to the next level. Without him the team functions just fine, but adding his leadership increases all damage by 25% and his heals keep them attacking.

Runes: Speed runes and primary speed. To say speed is the best stat for most characters is an understatement, and that rings out true here. You want to heal as often as you can. More speed gives you more chances to heal. After speed we prioritize tenacity, most. We don't want to lose control of our healer. Health is a fine option as well, as a dead healer can't heal you. 

Artifacts: He has his own artifact as well and their secondary effects seem pretty good, need tested to be out. Damage is what I would pick as his attack stat. Balance out the lowest tenacity, health or armor as his defensive stat. They all feel fairly even for keeping him fighting. 

Non Humans

After getting past the legendary Mor'doom unlock, we can expand non humans into the team. The most outstanding is adding Nightiel to the group. Unfortunately, we have to remove Eric to do so, but I think that is the best choice. Nightiel has great synergy with Solius and makes the third mage for the team (meaning they will often be invisible). Her buff to everyone's attack and removal of random buffs and debuffs can also make a real difference.