How about instead of the current drakes

Gold Drake: Gives 200/250/300 gold to everyone on your team when slain (200 the first time, then 250, etc) Cloud Drake: Gain 5/10/15% tenacity for everyone on your team when slain Water Drake: Gain 2/4/6% spell vamp or lifesteal (adaptive) for your team when slain Lucky Drake: Your team gains 4/8/12% crit chance or 4/8/12% CDR (adaptive) Elder Drake: For every drake your team has slain (excluding elder) your team deals 5% of its damage as true damage, up to a cap of 25%.

Elder Drake would work the same way it does now where it only spawns after like 30 minutes or something and other drakes cant spawn after that time