Blood Focus
At 3rd level, a water warrior adds 1/2 their elementalist level to all damage dealt with Drowning blasts.
At 9th level, This bonus damage increases to become equal to their elementalist level, and the elementalist may use his class level as his caster level when using the Water package from the Nature sphere. This stacks normally with caster levels gained from other sources.
At 15th level, the bonus damage increases to 1.5 times their elementalist level, and they gain a +2 bonus to their caster level with the Blood Sphere
This modifies/replaces favored element.
Bloodwrack
When using your Drowning Blast, you can spend a swift action to force a Fortitude save from the opponent, if they fail, they are considered to be under your blood control for a number of rounds equal to 1/2 your blood bender level. You may also spend a spell point to force them under your blood control as if you cast it normally when using blood wrack.
This replaces Elemental Defense
Bloody Motion.
Greater blood circulation helps you to move more quickly, giving you a +20 bonus to your land speed, at 13th and 19th level these increase by +20 feet.
this replaces elemental movement.
Master of Blood
At 20th level you become a master of the careful art of manipulating the body. You become immune to Poisons, Diseases, and bleed damage, and no longer Age.
Shouldn't there be something that gives you the Blood sphere for free?
Probably. though the "Warrior" archetypes that I vaguely based this on don't give their respective Nature for free.