Seven Star Tattoo

Original Seven Star Tattoo

There is no Seven Star Tattoo (SST) in the original series.

The inspiration to create it was out of the filler episodes about Hoshi Gakure and their "star" they'd train with to gain exceptional skills and obtain a purple chakra that was stronger than anything they knew.

Constant use did wear the body down.

Seven Star Tattoo in SL

The Seven Star Tattoo, having no linkage to the series, was designed to be a counterpart to the Curse Seal, which basically boosted the power of Orochimaru's followers for a price.

The tattoo starts with a base you can obtain, and you have to get the ink for each star in order to complete the tattoo.

Like the name, you need 7 stars.

A complete tattoo will boost your powers and obtaining all the ink is extremely difficult.