I think if you mix the bloodlines you can get exactly what you want as far as powers or spells you want to use. As this is just the interest check I can go into more detail as to how that works. But for now the spells or abilities you want if you're not sure it will work with your bloodline ask me. I have a way of knowing if something is matching a bloodlines affinity. Such as Divination, Evocation, Transmutation etc. (other D&D lore terms)

Also their relation to water isn't everything about them. It's mostly lore based. But for a Arena I decided not to bore with that.