A flying first-person shooter from the sadly defunct Bullfrog Productions. It was fairly successful commercially, but was limited by high (at the time) system requirements and people not knowing quality when they see it. I am, by the way, a massive Bullfrog fanboy.
The game involves flying around killing things to claim their mana. You win each level by having a certain percentage of the level's mana stored in your castle. Castles are also your respawn point, and must be grown as you acquire more mana.
Most of the monsters are fairly passive, more likely to defend themselves than assault your castle. Unfortunately, there are enemy wizards on most levels who have the same powers and goals as you. They will try to tear down your castle to steal your mana, and (like you) will respawn at their castle as long as it stands. They are the real threats.
The intro video explains the backstory much better than I could:
www.youtube.com/watch?v=WI3n0JpEyAMYou are a wizard. THE wizard, now. It was a long, difficult, and often tedious struggle, but you won. You "restored the fractured worlds to equilibrium", your dead master said. Apparently that's guru-speak for "immolated every thing, living or dead, that stood in your way".
It didn't take much to be in your way. Anything containing mana, that golden essence of magical power, needed to die. Rocs, trolls, vast crawling wyrms, even the mighty wyverns fell to your spells. You harnessed their mana, stored it away in your keep, and channeled its power to continue your search.
It wasn't greed. You NEEDED the energy to fix everything. To remake the world from the tiny splinters your master's arrogance had made of it. The unlimited power and deaths of your rivals were... unavoidable bonuses.
Fortunately, most humans don't contain mana. Most. You had no choice. Civilization is flourishing now, thanks to what you had to do. Not that they ever thank you. They don't talk World-Shattering-Wizard-Speak.
But this brooding is only a momentary distraction from your main problem...
You are BORED. No rivals, only a precious few captive monsters, and the land-dwellers are inane as ever! You briefly wish that you understood their language just so you could properly snub them.
But this is intolerable. It has been HOURS since you killed something. You open your mind's eye and peruse your spells, which appear as somewhat vague icons.
How will you proceed?