1. Don't level up to much heros at the same time. It's very easy to get a champ to lvl 40, you just need to sacrifice 3 lvl 30 champs. 

But you need 4 lvl 40 champs to go to lvl 50. To get 4 lvl 40 champs you need 12 lvl 30 champs.

You need 5 lvl 50 champs to go to lvl 60. To get 5 lvl 50 champs you need 20 lvl 40 champs. To get 20 lvl 40 champs you need 60 lvl 30 champs.

Just do yourself a very big favor and don't lvl up anybody else higher than 40 until your Kael reaches lvl 60. You will end up with a bunch of lvl 50 and lvl 40 that can't kill anybody in higher stages. Make one champ lvl 60 first. He can farm food in the campaign: let your Kael run campaign stage brutal 12-3 together with 3 useless champs you just lvl up as food.

2. The champs you currently have, exept Kael and Armiger, won't be used later one. In the first week they may help to get through the campaigne, but none of theese will be used later. Just wait for better champs and lvl up your Kael.

3. Shiledguard is so overrated by some fans, but there is absolutly no point about this. He attacks all enemies with his A2, and if he lands a critical hit on each he could get an extra round attacking single target with his A1. So he combines an AoE-hit with a single-target-hit. That is basically the same thing, a rare like Dunestrider (Barbarian) can do in one attack with her A3. Nobody uses Dunestrider, nobody makes a big hype about her. Dunestrider has a much higher base atk than Shiledguard has base Def (on wich his damage scales), so Dunestrider (wich is not a good champion overall) just deals more damage than Shieldguard. The Cooldown of her A3 is longer than Shiledguards A2, he can deal is AoE damage more often, ok. Maybe he can farm in the campaign faster than other champs would. But what is your limitation in campaign farming, time or energy? Somebody made Saurus (another uncommon, Lizardmen) a 3 second campaign farmer. Great job! But if I spent all my energy in less than one minute or in 5 minutes or even in 10 minutes doesn't really matter.

Agree with Skadi, don't look too much into gearing Shieldguard and Saurus. They can be used as campaign farmers but you won't really have the gear to pull it off early game. This too might make you spread your resources too thin across multiple half-built champs. 

Focus on Kael, and open your shards since you need more champs to progress. Boosted rates for Ancients aren't expected to happen soon anyway. Good luck!

Thank you for your answer!

Okay, I will keep farming up to level up Kael and as you say, Armiger also will be my 2nd stacked champ. I think I invested too much into Skinner and Dhampir as they doesn't sound so promising later on for me. Also gonna stay with Shieldguard for a bit, gonna level up him to 40lvl, but should I level up Warpriest also to 40 level?

I love how friendly and active the community of RAID is.

As you say the Ancient shard boosts aren't coming, I opened 4 of them and I got:

Frozen Banshee (RARE), Sanctum Protector (RARE), Templar (RARE), Master Butcher (RARE). Should I focus on someone of them? As I looked into the TIER LIST, only Templar looks good.

Frozen Banshee you might like to keep for early and mid game Clan Boss fights as she is providing Poison sensitivity, which increases poison damage by 25%. I also used her in some dungeons like Dragon early on. Sometimes, there is an advanced quest which requires a rare champion to fight against Clan Boss...Frozen Banshee is the most used rare for that quest in my clan. 

The other three...just disguised chicken in my opinion.

You can lvl up 3 other champs to lvl 40 that help Kael to get through the campaign. Lvl 40 is not such a big investement and doing the campaign will give you big rewards as you get artifacts you will use for a while. From the champs you have right now a good campaign team for the start would be Kael - Warpriest (as healer) - Sanctum Protector (def buff for your team) - Dhampir/Templar/Shieldguard (as damagedealer against force affinity, where Kael is weak). You will probably not use them later on, I think Dhampir and Sanctum Protector are even to weak to do faction wars and could be used as food to bring Kael to lvl 60 later. But right now they are a good campaign team in normal.

Don't level up Armiger to early. He may be an uncommon, be he is really and endgame champion, used to do high lvl dungeons with his turn meter reduction against bosses. He is not good in the Arena, useless at the Clanboss (Clanboss is immune to turnmeter reduction) and doesn't help much in the campaign. Armiger is a dungeon specialist. Get 2 or 3 allrounders first to lvl 60.

Frozen Banshee is a really good champ vs. Clanboss and dungeon bosses like Dragon. The ammount of HP of this enemies is really big, poison damage scales with the enemy HP. Poison will do much more damage against these enemies than the normal hitdamage of your champs does. Therefore Frozen Banshee is a real top tier champion vs. Clanboss.