An entry in Fortnightly Topic Challenge #48: Unusual tag mix
My prefix hosted* talk to beat a killer from within.
My infix works for former bandit, shooting with their twin.
My suffix can be found in range of anime-like weapon.
My whole, while very powerless, caught peaceful man's attention.
The anime referenced on the second line is significantly more obscure than the others; the twin shares a name with a virtual shark.
As promised in a comment below: The anime from the first line and the third line have a similar spirit.
*Originally "...prefix lead a talk..."; my bad!