Some monsters wake up ambitious
The ordinary grind, ambushed by good news: out in the hunting grounds, some spawns come up as champions. Stronger, meaner, and carrying a much better purse.
A jackpot with teeth
A champion is the same monster you were farming, promoted: harder to kill and noticeably more generous when it falls, with boosted adena and drops. It turns a routine pull into a small event, and a good farming session into a story.
The night runs richer
Champions run on the world's clock: by day one is a rare windfall, but after dark they walk three times as often. The same grounds, the same monsters, a much busier payroll: night hunting is champion hunting.
Fields only, and that's the point
Raid bosses are excluded: champions exist to enrich ordinary hunting, not to stack multipliers on content that already pays. The system rewards being out in the world, which is where a living server actually lives.