This seems quite believable. Would look like this assuming the cycle works always the same:
Ordeal of Heliod
Whenever enchanted creature attacks, put a +1/+1 counter on it. Then if it has three or more +1/+1 counters on it, sacrifice Ordeal of Heliod.
When you sacrifice Ordeal of Heliod, (you may?) exile target creature. If you do, its controller gains life equal to its power.
This would make the Ordeals be of the form "put counters on the creature, when it has enough counters, sacrifice for a staple effect of that color" (red has Lightning Bolt, white Swords to Plowshares...maybe green makes a token? blue draws cards? black destroys?)