Sheena Fritz

Sheena is born roughly two millennia before the main story to Fritz, king of Eldia, and to Ymir, the enslaved concubine who became the first of all Titans, joining Maria and Rose as the third of the couple's daughters. Ymir dies in the wake of an attempt on the king's life, and Fritz immediately commands his daughters to devour her corpse so that the power animating her will not be lost. The grisly order works, and Sheena absorbs a portion of the Titan ability alongside her sisters.

She presumably lends that power to her father's imperial conquests in the years that follow. On his deathbed the king leaves her final instructions: produce as many heirs as she can, and let those children consume her spine when she dies, a cycle to be repeated down every generation of the family line so that Eldia might dominate the world without end.

Through the forced cannibalism of her mother, Sheena holds one share of the original power of the Titans and stands among history's first Intelligent Titans. The ability cannot simply die with its bearer; it transfers whenever a successor consumes the spinal matter of the previous holder, exactly the mechanism her father demanded she perpetuate.

Her portion of the power passes to unknown successors after her death, as do her sisters' shares, and across the generations the inheritance fractures until nine distinct Titans serve Eldia. More than 1,800 years after Ymir and her daughters die, Karl Fritz raises three enormous barriers on Paradis Island out of countless Colossus Titans and names each ring for one of the three sisters. The innermost circle becomes Wall Sheena.