7M HP, what's the problem? I hit a bare minimum of 10M You'll get there one day

Lol, they are called Super Elite Guards and can be up to lvl 51 (which is 51 million Inhibition Points ("HP")) as far as i saw. While normal Elite Guards have no level/HP limit as far as i know (the strongest i saw was around lvl 1500 or something like that) But yeah, to defeat those you need big Base SED power, all Special Effect Cards from Event gacha to multiply your base SED and strong friends who have all of that. Keep in mind that you can also buy for Pero, and use Sexual Energy Drinks on those bosses to halve their Inhibition (HP) when you find them, but only before you attack them for the first time. You can also use Elixirs (also bought for Pero) to drive them away, to be able to find another one, which may be weaker (or stronger). Or you can also do a 1 Focus attack on some other guy's Elite Guard or Super Elite Guard, and wait, until they finish it off - then you'll also get an "elimination count" and be able to find another EG or SEG for yourself.