From DariaWiki

Tania is a classmate of Daria's and backgrounder given name via seating chart in "Cafe Disaffecto".

She's a fan of Mental in the Morning, left horrified by Daria's comments in "Jake of Hearts", and is hanging out with Kelly at "Cafe Disaffecto".

In fanfiction, she's a member of the Anime Club in cfardell_Brenorenz29's "Quinn's Code".