Here is the full list of all 25 Royal Heroes achievements.
Veni Vidi Vici!
Discover all air spells
Discover all water spells
Discover all fire spells
Discover all earth spells
Sacrifice a weak one to make your army stronger
Do something useful. DOIT!
You can't be a winner all the time
Dont be a Batman - do it!
Flawless victory - no casualties
Hire a 4 star hero
Discover all void spells
Warp a few times
Find and restore a famous weapon. Get Warping Power increase.
Find and 'pet' at least 10 sheep
Clear a whole other dimension. Get Warping Power increase.
Collect the whole set
Craft a weapon that only the worthy can wield
Come to dark side. We have cookies. And extra spell slot.
Find and kill all of famous vampires