Jadelight Champion

Ascend (If you control ten or more permanents, you
get the city's blessing for the rest of the game.)
Whenever Jadelight Champion or another Merfolk
enters the battlefield under your control, put a
+1/+1 counter on target Merfolk.
As long as you have the city's blessing, if you would
put one or more counters on a Merfolk you control,
put twice that many of those counters instead.