The Eris side story Chapter 1 is out now on Gangan Online : r/mushokutensei

DISC] Mushoku Tensei Eris Gaiden - Ch1.1 : r/manga

Mushoku Tensei Anthology: Eris' Side ch1 : r/mushokutensei

Mushoku Tensei: Roxy Gets Serious Spinoff Manga Ends With 12th Volume (Updated) - News - Anime News Network

SF & Fantasy Manga – 2 Label_Gangan Comics UP! – Japanese Book Store

No Matter How I Look at It, It's You Guys' Fault I'm Not Popular! - Wikipedia

Eris Gaiden new chapter : r/mushokutensei

A new Mushoku Tensei spin-off manga series titled Mushoku no Tensei - Eris Gaiden by Okano Yuu & Higake Take based on Eris when she separated from Rudeus Start on Gangan Online

FEATURES - Manga Bookshelf

SF & Fantasy Manga – 3 Author_Rifujin na Magonote – Japanese Book Store

Mushoku no Tensei - Eris Gaiden

Read Mushoku no Tensei - Eris Gaiden Chapter 1.full-eng-li Online