Ok, so I've been playing Tynon for a month now so i can't say that i'm a Veteran or pro in this game. The only thing i'm going to discuss here is about my build on"Smoulder".

Formation:
Because of Smoulder's skill attack which is AoE; i always try and place him at the back. I haven't seen anyone who use him as a tank and i'm guessing you won't either. During boss fights i always remove him in my formation and change to someone who can do more damage and doesn't miss much.

Runes:
These are the runes that i use for my mages... There are 10 runes here because i tend to change them depending on who/what the enemy is(You should do this as well)
adept -Increases Skill Damage
Burliness - Red Phy damage taken
Dextrousness - Resilience
Flintiness - Red skill damage taken
Intenseness - Increases Magic Damage
Messiness - Reduces Magic Damage Taken
Nimbleness - Increases Dodge rating
Preciseness - Increases Hit Rating
Vitality - Increases Max HP
Resistance - Increases block rating
N.B.
1.As you can see i don't use Runes with break and critical because i haven't seen any hero that blocked magic damage. I haven't seen my mages do crits as well. I already discussed this with other players and all of them agreed with the two runes as incompatible with mages.
2.I saw a post of someone suggesting that there should be a mage rune that can be redeemed for 100 fragments. I'm not sure if the developers took this into account... Guess we have to wait and see

Well, that's all from me.... Let me hear about what you think