Pactio Sanguina

Pactio Sanguina is a blood bond that the Sanguinese use to replenish themselves with the type of blood that is best for them.

On Mikan's case, she has a Pactio with both Ren and Lei. She quickly regains energy when she drinks their blood. A person's race also affects the rate of recovery of a Sanguinese; Celastrans give the quickest recovery rate, much to Mikan's convenience.

A Pactio affects the blood bonded individuals physically and emotionally. Mikan seems to be very attached to Lei and Ren and vice versa. When she is very weak, she prefers their presence. Likewise, Ren and Lei are compelled to protect Mikan.

Guizu once remarks regarding Mikan's pactios that "they're sealed with a kiss!" which Mikan denies, saying that it is just a rumor.