The decision to keep the main cast of My Abilities to just four characters rather than expanding the cast is understandable. Crimson Vow is the characters' group. Since the story was mostly about Crimson Vow, Millie and the other characters got the same amount of attention.
The Cel Block: Anime Reviews & Analysis for the Gen-X Fan
Sub title page content

By Pinned Up InkInModern Anime Reviews,
Rent-a-Girlfriend,
Rent-a-Girlfriend Season 2
Rent-a-Girlfriend Season 2 Review: Comedy, Romance, and Growth

By Pinned Up InkInMiss Kobayashi's Dragon Maid,
Modern Anime Reviews
Miss Kobayashi's Dragon Maid Review: Comedy Anime Gem

By Pinned Up InkInNews,
Sekiro: No Defeat
Sekiro: No Defeat Anime—Release Date, Story & Streaming Info

By Pinned Up InkInCarole & Tuesday,
Modern Anime Reviews,
Music
Carole & Tuesday: Anime Where Music Triumphs Over AI

By Pinned Up InkInChainsaw Man,
News
Chainsaw Man Compilation: KICK BACK Remix, Artistic Impact & Film Analysis
Continue Reading