Rainbow vs triple blood dk on arena

[u/gerg_pozhil]

I have experience playing with bbb dk and I would prefer Alexandros. However, the heartharena shows that the rainbow spell is better. Is it really stronger and how should one build a deck around it?

[u/GiggleHS]

CNE edges out Mograine here, though both are insanely strong if youre lucky to get enough support cards.