There are two decks mentioned in the topic, firstly, the Thadius-SawBlade deck, and secondly, the IrradiThad deck. As stated, if you're under level 15 and looking for a deck to help you breeze through your missions, these two decks are the typical no-brainer decks for you to use. That being said, the missions actually do help you think through how you should be constructing your attack decks, and experimenting with different deck types is always a good way to learn the game. Also, do remember to take a look at some of the decks that are on some missions, as those also give you an idea of "faction-specific" deck types.
1. Thadius-SawBlade - The el-cheapo deck, in all sense of the word
Good to use the moment you unlock SawBlade in Arena, and Thadius is a Mission 17 Reward Card. It's extremely cheap, contains multiple of one card, and is good up till Mission 30+ (correct me if I'm wrong). However, please do not use this as a defence deck for faction wars, as Sawblades get eaten, chewed up, and spat out way too easily. An EMP effectively reduces all SawBlades on the field to 1 hp, and unfortunately, is only good as an attack deck for low level faction play.
This deck should only be used for missions only.
Thadius
10x SawBlade
2. IrradiThad - the cheap, effective, annoying deck that never grows old
Irradiated Infantry, gotten a reward card from Reputation with the Purge (similar to Pummellers), is the upgraded SawBlade for later missions. 1 turn, 2 attack 3 defence, poison 1, just makes it much better than SawBlade. You can swap Thadius for Freddie (Heal all Imperial 1) or Eva (Heal Imperial 2), according to your preference. You'll still find this as defence decks in some top factions.
Pros
Quick, cheap, effective, annoying. Play against it and you'll find out why it's annoying. Good initial choice for low level players who do not have a large card pool to choose from.
Poison is the icing on the cake, taking away an extra hp every turn. Also, 1 wait and 2 attack makes it useful against Dracorex decks.
Useful for missions and as a defence deck, less so as an attack deck.
Cons
Easily killed by strike, opponent gains the upperhand after using an EMP and having enough Strike cards on the field. Also susceptible to Counter decks.
Can be stopped by Armor 2 cards.
Notes
Once you have a bigger card pool, experiment and try other defence deck builds if possible. Most of us might not have the time for the game, so if you can't experiment, more deck suggestions will be brought up, to coordinate our defence better. Please try as much as possible to keep away from using this as a defence deck, as many players are already prepared for the IrradiThad decks, and can easily win it.
- kanichan wrote:
- Also note that instead of just spamming 10 x II, you can also modify it a little if you get cards that fit in the deck like:
-Dominator/fighterjet/tiamat *makes your deck stronger against flying units*
-fortifier/sawblade *gives you more chance against amored units*
-titan *to give you a fighting chance against a structure deck.
As you can see you can modify you II spam deck to make it stronger against certain decks. So Always keep in mind to look at what is most commonly used in the decks you are fight in a war so you can modify your II deck to give you more wins. 
