I Summon an army deadric overlords using barrels of acidic elephant-piss as weapons. Then, Melt down whatever defenses your hill may have and I build a giant fortress made out of reflecting crystals. Then, I build a lake of the same acidic elephant-piss as my army uses, and i set up a giant electronic laser system that kills anyone near the fortress. Then, i build some robot guards who's immune to everything, and place 'em all around the lake as security.
...My hill.