Future mythic details that I know of:
Jotnar Stormshield
Mythic Stormheim Divine/Giant
Spell: Thunder Javelin (22 Blue/Red/Yellow) - Deal [Magic+5] true damage to an enemy, boosted by allies with Barrier and Giant allies. [x5]
Traits: Giant Bond / Huge / Storm Shield (Give a random Ally a Barrier on 4 or 5 Gem matches.)
Flavor Text: He doth bestride the narrow world like a Colossus.
Requires Blood and Blade arcanes.
Will arrive in 8 days.
Ketras the Bull
Mythic Wild Plains Divine/Tauros
Spell: Blood Hunger (Brown/Green/Red ) - Deal 4 damage to an enemy, boosted by my Attack, Life and Armor. [2:1]
Traits: Tauros Bond / Armored / Raging Bull (Gain 2 Attack, Armor and Life when matching Red Gems.)
Flavor Text: Gives you wings…
Requires Forest and Beast arcanes.
Will arrive in 36 days.
Stonehammer
Mythic Khaziel Divine/Dwarf
Spell: Ancient Wrath (Blue/Brown/Yellow ) - TBD
Traits: Thick Head / undefined / Unbreakable (Reduce damage from Skulls by 80%.)
Requires Shield and Mountain arcanes.
Will arrive in 71 days.