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