Decimate — When Legate Lanius enters, each opponent sacrifices a tenth of the creatures they control of their choice, rounded up.
Whenever an opponent sacrifices a creature, put a +1/+1 counter on Legate Lanius.
"Victory shall be ours, it shall be swift, and it will be honest, purchased with blood."
For example, when Legate Lanius's first ability resolves, an opponent who controls between one and ten creatures will sacrifice one creature. An opponent who controls between eleven and twenty creatures will sacrifice two creatures, and so on.
Random a card of Magic: The Gathering (MTG), but you can also roll the D20 dice, random a Planeswalker, have fun with the random rules and more.