>>280437430
>Guardian Spirit sounds like a yet to be trodden shounen protagonist archetype
There's a recent manga that kinda does this. It's Daiakutou Shonen, a manga about a boy in a MHA-like world with capes that hates the heroes vs villains dynamics and wants to become the ultimate villain and defeat everyone. One of his powers is a near-invulnerable muscular ghost-like monster with his own personality that protects the boy and used to be his imaginary friend/tulpa before he got his powers.