this seal does two things one it turn the person more dragon like to be more exact more eastern type dragon the person form a tail as well there skin be more reptilian like and the ablity to fly as well the other half is this seal job is it a summoning seal calling 4 great dragon kings

Ao Chin
Ao Kuang
Ao Ping
Ao Shun

( looked this in my encyclopedia of magical creatures there part of history look them up )

these dragon controlled rain and the water, like the rivers and oceans this making powerful summon and ally