Aka (猩) is Enten’s red goldfish. It drinks an attack. Speaking Aka plus the absorbed name spends that attack back for a short window. It is not a general shield. It is a mouth with a timer.
Red next to black
Kuro cuts. Aka returns. Nishiki clothes. Hokazono wanted white, black, and red because the hero’s coat is already stained. The Volume 11 jacket still pairs Aka and Kuro on snow. This page is the drink, not the cloak. Official chapters: VIZ / MANGA Plus.