Simple skript that allows you to announce in chat and display via command kill streaks.

How to install:
Install Skript 2.9.3 ( Link)
Open folder: Plugins » Skript » scripts
Upload file Killstreak.sk in that folder
Log into the server and run the command /skript reload Killstreak.sk

Useful Commands:
/killstreak (killstreak.use)
/resetkillstreak (admin.resetkillstreak)

PS: You can edit the code yourself, it is not copyrighted.