If you want the Pegasus Scroll, you kill 5000 troops.
You can only participate in this event once, so once you've turned in that screenshot for that amount, that's it.
IF you kill 100 000, you do not qualify for everything below that amount ( no tiers).
Additionally, once you've entered, you cannot enter another screenshot of a different amount. E.G.: One entry of 5000, another entry for the 30 000.
Have fun storming the castles