Who's tougher?

Roco and lava are the two toughest dragons in the game currently, not including heal, but I've always wondered, out of the two who is more durable at the same lvl with same stones?

Crystal all the way! haha
but if its between roco or devil i would probably go with roco just because of his massive health

Roco, not only got massive hp but also reasonable defense and better bombs than lava. Both roco's bombs have a probability of stun plus rock does massive damage and can break blocks in one hit