Tatiseigi is Lord of the Atageini and is one of the premier lords of the Padi Valley association. He is conservative -- some say ultra-conservative -- and is described as hidebound by a number of the people around him, and especially by people who oppose him or who belong to groups which he disapproves of.

Tatiseigi disapproves of a great many things, among which are 'trains, telephones, television, space travel, humans, Southerners, Taibeni, west coasters, or anything ever imported from those sources,' as stated in Deceiver. He is most often described as being at odds with various persons or clans, but seldom as being in outright warfare with them.

He is considered a sharp, able politician and one of the prime authorities on porcelain in the Western Association.

Tatiseigi was once the lover of Ilisidi and may still hold that favor with her. His sister is Muriyo, mother of Damiri, who is the consort of Tabini, aiji of the Western Association. Cajeiri is his grand-nephew.

One of Tatiseigi's personal bodyguards is Rusani.

The clan colors of the Atageini are white and pale green. A symbol of the Atageini is the lily.