(Tip for building... the first theme deck daily mission will give you half of most of the uncommon cards you need for this deck, the theme deck you buy in the store will give you the other half, meaning you can build this deck for cheap.)
This is a cheap deck to help you through early Ranked and Casual, as well as Gauntlet Masters. This deck had a 75% win rate up to Gold, where it slows down a bit. The trick is not to give up early, especially if you have Katra out. As a general rule you will take damage, however this is a healing deck, so don't sweat that too much, once it gets running the healing and buffed up units start rolling in quick. I don't know how many times I've had the opponent say "An honorable fight" or "I've got you now" only to end up defeated because they underestimated Katra and the Aspirants. This deck takes some getting used to, for instance if you have a Sanctuary Priest out always, drop your mob that buffs up from health gain before you drop Power, if you can. I've actually waited til I can drop a power then Katra, especially with decks with torches, so Katra can't be one shot right out the gate by Torch and Extraction.
I hope this deck lives up to your expectations. It's been revised several times and you can look at the edits, but I think for a cheap inexpensive deck, it can get you to at least Gold without too much of a struggle. It wont do well against meta decks with a lot of legendary cards, however early on it will make the trip a little easier while you're building your Meta deck or just trying to earn some chests in casual and ranked.
Cult Aspirant
x4
1
Sanctuary Priest
x4
2
Cabal Cutthroat
x4
2
Oasis Seeker
x4
2
Temple Scribe
x4
2
Vara's Favor
x4
3
Scorpion Wasp
x4
3
Skeeter
x4
4
Beckoning Lumen
x2
4
Deathstrike
x4
4
Katra, the Devoted
x4
4
Xenan Fanatic
x4
5
Colony Matron
x4
Shadow Sigil
x7
Time Sigil
x6
Diplomatic Seal
x4
Seat of Mystery
x4
Xenan Banner
x4
View Deck on Shiftstoned
I'm tinkering around with the deck and to improve it's consistency a little bit, I removed 4 Vampire bats and 4 Cabal Cutthroats and added in their place 4x Oasis Seeker (they trigger Katra before the combat happens, making trades a little better, I feel) and also added 4x Amber Acolyte, cause I was having power issues with this deck sometimes, especially in the early game. They'll also thin the deck so, it potentially makes your next draws a little better.
Only after those changes, I was able to win through a whole Gauntlet with this deck. I'm also considering ways to add more card draw or deck thinning mechanics, I'll let you know if I find something interesting. Try those changes though and let me know how it goes for you.
But gauntlet tends to try and match you every now and then against decks that can counter your strategy well. I felt the need for more card draw in this deck because, in it's core, it's a combo deck. Combo decks need a lot of card draw to make the combos reliable enough and to keep them going.
With this deck as you designed it (and like I said, I tried it a lot), often I'd find myself stranded on power and small creatures on board that couldn't do much without the sinergies. Or the strong combo cards but no healing effects, drawing power after power.
Sometimes I'd get Katra down and start the combo but she'd get removed the turn after and then I had to wait, without any draw engine other than Temple Scribe for another Katra to show up to keep going.
I don't know if I'm explaining myself well here but what I mean is that sometimes, I'd commit cards and spells into a combo to accomplish a stall or get an advantage then the AI finds a way to disrupt it somehow and you're left with little on your side and waiting on top decks, no reliable way to reload and play from behind. You see what I mean there?
On my tinkerings right now, I currently removed the Cult Aspirants and replaced them for some other cards to try out and I have to say I'm not missing them at all. Sometimes they'll stick and do some work but most of the times, for me, they won't stick around on the board. when using it early, it'll require a lot of mana or 2 turns setup to get him going and in this time, the AI removes either him or whatever is beside him to help trigger lifeforce (usually a priest with empower heal or something like that).
I ended up cutting him completely, but I found another interesting sinergy with a couple cards I added. Those were 2 Friendly Wisps and 2 Beckoning Lumen.
Friendly wisps don't have many targets to trigger his ultimate but he does have sinergy with the Invocation, when you can summon an >5 guy. And he also synergizes with Lumen. I was able to trigger him a lot and these two cards felt more useful to me than the Aspirant.
On a sidenote, there's another Lifeforce deck I saw SirRhino playing in high Masters lately with a good amount of success and I've been trying it in Gauntlet (with some replacements though, mainly because I don't have Ayan). That deck is feeling a little more smooth to me currently and less dependent on Katra to win games. Here's the decklist for you to have a look:
Lifeforce - Sadistic Devotion
As you'll see there, there is some more card draw available in becky's and favors, as well as scribes. As for Ayan, I felt like I needed more removal in gauntlet so I replaced him with your choice in the 3 drop: Wasps. I think it can be tuned a bit better for gauntlet, but It's working well for me currently (the Valkyrie is godly) and games will get out of hand quickly with that deck.