this strongly reminds me of the intro to the chimera ants arc from HxH, all these lesser ants show up but none have real power, but off unknown there's something new...something nasty overpowered...and they're just walking in totally unprepared for it
well, except for the fact that in this series MC is OP as hell himself so he's probably gonna be the one to put it down, instead of getting stuck on a mere guard while others kill the HxH king-equivalent