It is based on the Demon Slayer: Kimetsu no Yaiba anime and manga series.
Akuma no Isan (roughly meaning Demon’s Legacy) contains Skill Trees, Quests, Races, Families, Breathing Styles, Blood Demon Arts, multiple Nichirin blade colors, fusion Breath Styles and more!
When you first load into your world, you will be greeted with a prompt to look down. This will randomly assign you to a Family, a system that gives you inherent traits outside of your Race and Blood Demon Art/Breathing Style.
These Families will give you different buffs, for example Rengoku family allows you to Unlock a special move on Flame breathing, And Kocho family will Make you deal poison on hit, but your punch will be slightly weaker and so on.
To become a Demon Slayer, use a breath book (for example a Book of Thunder). These can be found in loot, or obtained through Quests through hashira that is roaming around your world.

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