Use everything you've got, excluding unstoppable/impossible terms which includes .
Rules can't be anymore complected, all you need to do is display how you've captured the hill becoming it's king and declaring your capture with or without using flags.
Poster 1 : I've captured the hill, nothing complex, just captured it, it's mines...
Poster 2 : As I ambushed him with my stealth cloak I shot him dead. The hill is now mines mu huahahaha.
Poster 3 : I used my heat seeking missile on the stealthed person now the hill is mines muhuahahaha.
Poster 4 : I used my hulk potion turning me into the incredable hulk now the hill is mines muhuahahaha.
You don't need to declare it being yours, you've simply captured it by slaying or defeating your opponent.
I'll start now.
A little girl with cuteness stats has captured the hill making it impossible for anyone to capture it.
She's the king of the hill now.