Rhaegal, Sky's Inferno

Flying, first strike, trample, protection from red, green and white.
Whenever a creature you control enters the battlefield, put a +1/+1 counter on Rhaegal, Sky's Inferno and you gain 1 life.
{r}{r}{g}{g}{w}{w}, {t}: Other creatures you control get +X/+X until the end of turn where X is Rhaegal's power.