It doesn't have a spell for now, so it's impossible to tell how good it is yet.
Still, here's all available details for future mythics (Though Stonehammer did not change, I put him in as well for completeness sake).
Mythics for April,May,June - OUTDATED:
REMINDER: ALL FUTURE TROOP DETAILS ARE SUBJECT TO CHANGE AT ANY TIME. (Retrieved 2017-03-20)
Mythic / Khaziel / Divine Dwarf
Spell: Ancient Wrath (22 Blue/Brown/Yellow) - Cause Burn and Stun to 3 random enemies. Gain [Magic+1] Life.
Traits: Thick Head / Warded / Unbreakable - Reduce damage from Skulls by 80%.
Requires: Minor Earth, Arcane Shield, Arcane Mountain Traitstones
Max stats: Attack - 14; Life - 37; Armor - 18; Magic - 6 (When fully ascended and level 20)
Flavor Text: Sing along with me...
Will arrive in 18 days (2017-04-07).
Mythic / Dragon's Claw / Dragon
Spell: Last Shadow (Brown/Red/Purple) - TBD
Traits: TBD / TBD / Confligation - Burn all enemies on 4 or 5 Gem matches.
Requires: Minor Fire, Arcane Lava, Arcane Dark Traitstones
Will arrive in 46 days (2017-05-05).
Mythic / Silverglade / Divine Beast
Spell: Rainbow Spirit (Green/Yellow/Purple) - TBD
Traits: TBD / TBD / Rainbow Link - Gain bonus Mana from Gem matches.
Requires: Minor Wind, Arcane Light, Arcane Plains Traitstones
Will arrive in 74 days (2017-06-02).